ABSTRACT. After considering various alternatives and options, a filter for filtering water to make it potable is presented. It consists of an optional prefilter, a Katadyn ceramic filter, and an optional activated carbon post filter. There are several options for forcing water thru the filters. All are based on the principle that a small pressure for a long time is more efficient than a high pressure for a short time. These include elevating a tank to provide pressure due to gravity, useing water that is already elevated, amplifying that pressure with a hydraulic ram, and useing an electric pump.


   I have been exploring several low cost options for purifying drinking water. The lowest initial cost and least energy efficient method is to heat the water to boiling. Heating it to 149 degrees F for 6 minutes (pasteurization) kills the major pathogenic organisims including virus.  Energy requirements can be reduced to a reasonable level if a very good heat exchanger is used to heat the raw water with the pasteurized water. Surface water should be prefiltered with the 1 micron prefilter discussed later and will benifit from the activated carbon filter discussed later.  The main problem with this is that a thermostatic valve is required to regulate the water flow. Years of experience with these valves clearly shows that affordable commercially available valves are far from hippy proof. A write up on this method appears in Home Power magazine #52. If you wish to construct such a device, please consult with me regarding the heat exchanger and valve.    There are also some possibilitys with batch processing with a combination of chlorine and hydrogen peroxide, again not very hippy proof. Contact me if you want more info.


   I believe that filtration will be the most generally useful method in the "Rainbow environment". The systems I present below are intended to make filtering affordable to the average and large kitchen. Further investigation revealed several general principles: Contaminants in water vary so widely that definitive answers to the question of what filters are best or their expected life cannot be given. A completely hippy proof system is not possable. Hippy proof withdrawl of water is possable, installation is close, but cleaning the filter I recommend is not. This does not mean that unsafe water may be

produced, but that poor cleaning practices will result in poor filter life or low filtration rates. Anyone cleaning the filter should read the section on cleaning. Some have ruined a good filter by totally disregarding the cleaning instructions. The best system configuration will vary greatly with the designed capacity and local conditions. It is intended to be kitchen sized as a minimum but is suitable for an individual or to to provide over 2 GPM continuously when used with hydraulic ram, electric or other pump. It is easy to setup and intended for a camp of short duration such as a rainbow gathering but not for a group that is on the moove.  I can provide more detailed drawings by US mail on request, but unless you have the parts and facilitys on hand, you will probably want to buy atleast part of this ready made. My mailing address is Wayne Robey, 215 S. 6th St., Lafayette, Indiana 47901.




   As the filter becomes finer, the flow rate decreases rapidly. Removal of most virus by filtration is not practical, if this capacity is desired, it would be desirable to filter water thru a good prefilter into a storage tank, treat the water with iodine or chlorine, and after sitting long enough pass it thru a high capacity activated carbon filter. If the carbon filter is not cleanable, it should have a suitable prefilter to keep it from cloging. In the North American wilderness, virus is not generaly considered to be a problem but a large gathering is not wilderness. The details of this process are not included in this paper. For complete removal of microorganisms (I take virus to be a particle not an organism.) the generally accepted requirement is .2 micron though .4 micron works nearly as well, (E-coli is one organism that could occasionaly slip through a .4 micron membrane filter but that is not disatrous.) while cryptosporidia and giardia vary, some believe that they are readily removed with a 2 micron filter but as protozoa divide, a finer filter is required. One thing to watch here is that some .4 micron nominal filters will pass a signifigant ammount of 10 micron particles and are only useful as prefilters. In general a non cleanable filter will pass more water initially but have a much shorter life than one that can be cleaned many times by removing the contaminated surface. Water quality from a questionable or contaminated source varys greatly and cannot be predicted with any confidence.  Specifications for typical or maximum life in terms of gallons of water filtered are meaningless. Since there is no standard water for rating filters and particle size distributions vary greatly, these advertised lives cannot eaven be used reliably to compare filters. I have seen the cleaning frequency change by a factor of 5 from the same source over the period of a week. Water from the Wabash river reduced the flow of a Katadyn 1040 filter to .6 of the inital value after 2 gallons, at the 1996 North American gathering 160 gallons of spring water was required when useing a 1 micron prefilter. Deep well water will usually require more than this, while pure water will never clog the filter. At the 1998 Ocala gathering, fine particulates penitrated deeply into the Katadyn ceramic. For these reasons, a great deal of surplus filter life should be available. For general use, I settled on three of the Katadyn ceramic filters, the #4 (article 1040), the LP-K700 (article 1700) and the CERADYN (article 20743). All have a nominal pore size of .2 microns and are well established as reliably producing safe water. The main differences between them are shown below. All have advantages and disadvantages. The main advantage of the 1700 is the high thru-put to size ratio but has a much shorter life. A good fiting housing can be easily made from readily available parts. The 1040

provides long life under favorable conditions, best ruggedness due to the metal construction and the tension maintained by the metal on the ceramic and better filtration of particles smaller than .2 microns. The 20743 combines the short life of the 1700 with the size of the 1040 for the highest thru-put. The flow rate as a function of pressure is linear over the useful range. The new flow rate is not fully restored by light cleaning due to the fact that the ceramic contains some large pores which increase the inital effective surface. In addition, clay, smoke, carbon black, and possibly other inanimate particles exist as a continuous distribution of sizes over the .05 to .3 micron range. Virus also exists in this range but clay is the most common problem. Some of these will penitrate the ceramic to great depths. This is a greater problem with surface water than spring water and much worse if the water is mudy due to a recient rain than if it is clear. This should be kept in mind when selecting a gathering site. This has more effect on the #1040 than on the #1700 because of it's greater life. On the other hand, lake water filtered thru a new #1700 at the 1998 Ocala gathering was not as pleasing as that filtered thru the #1040 due to the greater ceramic depth of the #1040. If the water has been favorable, the #1040 filter approaches the performance of the #1700 as it ages. The chart below shows the conversion between clean filter, instantaneous, and average flow. The cleaning point is the instantanious flow when the filter is taken down for cleaning. The quanity filtered is the water filtered in arbitrary units before the filter needs to be cleaned again. (The conversion from these arbitrary units to gallons depends on the water quality.) Since each cleaning removes about the same ammount of filter ceramic, this number is inversly proportional to filter life. It appears to me that for system sizing, it is wise to plan on cleaning the 1040 filter when the flow is half the initial flow but in use, it is wise to clean less frequently when there is no shortage of filtered water.


Type   OD     Ceramic OD      removable  Length  Flow rate    List

              new   end life   ceramic            when new    Price

1040  2.175"  1.975   1.50   11.7 cu in  11.52   18.2 gpd/psi  $90

1700  1.813"  1.605   1.50    2.8 cu in  10.68   29.1 gpd/psi  $75

20743 2.163"  1.975   1.87               10.68   50   gpd/psi  $75


     item 1040     (flow in gallons per day @ 1 psi)     item 1700

quanity  cleaning average  Initial  *  quanity  cleaning  average  Initial

filtered  point    flow     flow    *  filtered  point     flow     flow

.6962     12.8     15.69    18.2    *   .4588    20.5     24.58     29

1.000     9.1      13.85    18.2    *   .7632    14.5     21.07     29

1.156     6.4      12.43    18.2    *   .9734    10.2     18.23     29

1.249     4.5      11.42    18.2    *   1.110    7.25     16.02     29


     item 20743     (flow in gallons per day @ 1 psi)     item

quanity  cleaning average  Initial  *  quanity  cleaning  average  Initial

filtered  point    flow     flow    *  filtered  point     flow     flow

.3654     35.31    42.1     50.0

.6444     25.11    35.75    50.0

.8637     17.63    30.41    50.0

1.000     13.22    26.80    50.0


I have developed filter housings for the Katadyn elements which are made from standard plumbing fitings as far as possable and are described below. The holder for the 1700 is based on 2" schedule 40 PVC parts, uses a friction fiting test plug and is the easyest of the three to make. The filter is supported on both ends for ruggedness. The best holder for the 1040 is based on the uncommon 2 1/2" schedule 40 fittings. I have been unable to find a suitable 2 1/2" test plug so it has to be made. An entirely different design which requires a lathe but allows the housing to be opened at the top has also been developed. Cleaning the filter is quickest with this design. The filter element is supported on both ends for ruggedness. The third holder can be used for either element and is based on 3" thin wall PVC parts. It is not much bigger than the second, uses much less PVC, but is not rugged. There is no pressure rating on the parts, some of which seem to be poorly made. This would be a good choice for home use at pressures not exceeding 5 PSI. This minimal housing supports the element as well as any of Katadyn's but I suggest that some means be provided to support the bottom of the filter elements during transport. A concentric prefilter could be built into this housing (probably useing polyester felt) but would be clumsy due to the frequency of cleaning the inner filter. This simple easy to make housing plus easy to reach input and output reservoirs provides much more water than the Katadyn siphon filter at a nearly equal price and much more than the drip filter at a much lower price. All of these holders require a special nut (for the 1040 element) or special tube connector (for any filter element) which I can supply. The friction fit test plug is used rather than a pipe thread fitting because I do not believe the pipe thread would have the durability required for the hundreds of cleanings required over the life of the housing. To keep any installation of more than one element managable, it is important to rigidly mount each filter holder as well an the input and output manifolds. Additional detailed information as well as the finished holders are available. I believe that obtaining the hardware from me is more practical than making your own unless you prefer a different design or prefer to use different materials.




The prefilter is useful when the main filter will encounter significant wear. When the water is clean or the use light, it is usually not worth the trouble.  While water varies greatly, my experience is that a 5 micron wound polypropylene filter will cut the cleanings of the Katadyn filter in half while a 1 micron pleated filter will cut the cleanings to 1/4 of that required without the prefilter. They are normally economical in that they do not clog too fast but the specifics vary greatly with the water. While all prefilters will always be cost effective with the 1700 and 20743 filters, it is less clear for the 1040. When cost savings with the 1040 is the prime concern, the 5 micron wound element can not be excluded. It is also more readily available.  The following example related to me from their use in Ocala lakes: With a 1 micron filter, 3 Katadyn #1040 elements operating in parallel will need to be cleaned after 40 minutes of use, without a prefilter, they will need to be cleaned after 10 minutes. One prefilter lasts about 1 day. If cleaning the 3 Katadyn filters takes 30 minutes and the system is used 16 hours a day, it will run for 14 cycles or 9.3 hours per day with the prefilter or 24 cycles or 4 hours without the prefilter. First notice the 130% improvement in running time and total water output with the prefilter. (This could be increased to 16 hours running time or another 72% by adding a fourth Katadyn element, and removing them one at a time for cleaning. Then one element would be down for cleaning at all times but the system would always be up.) Secondly, notice that one 1 micron prefilter lasts for 42 cleanings of a Katadyn #1040 element. During this time it saves 3*42= 126 cleanings. If the life of the Katadyn #1040 is 300 cleanings, it saved .42 of a #1040 element. The retail price of the 1 micron element is $5, and the #1040 is $90, so each of these prefilters saves $33 in system cost. Since I am not sure of the accuracy of the above lifetimes, the actual savings could be as small as $15. In order to avoid making a special housing for these, I have used a the common houshold filter holders with the input and output connections idenical for backwashing. To prolong prefilter life, installations which use more than 2 ceramic filters in paralell should consider useing prefilters in paralell to prolong their life.


                          WATER SOURCE SELECTION


Since the Katadyn ceramic does not remove most virus or chemicals, these should be avoided or treated by other means. While the cleanist water avilable should be used, two things should be kept in mind. Clear water can be loaded with bacteria and protozoa which quickly clog the filter. While turbidity is not a good indicatior, clay introduced by runoff is to be avioded whre possable because the size distribution can allow it to deeply penitrate the ceramic as explained above.




It may also be desirable to remove various chemicals but it may not be worth the trouble if precautions are taken in selecting the water source. Activated carbon and selective ion exchange resins can do this but have a variety of limitations so it is important to understand what you want to remove. In addition, as the filters age they give no indication of their effeciveness. Overall, this cannot be hippy proof. The most common problem with surface water will indicated by poor taste due to various metabolites. This will also be true for water that has been stored for a long time. This is also the easyest to detect and remove but minerals can also have an undesirable taste and will not be removed by activated carbon. Agricultrual runnoff is a potential source of herbacides and pestacides as well as nitrates, (and clay which is another good reason to avoid it). Toxic metals can result from mineing or other industrial activity. Chemical contamination can result from small scale activity and be unsuspected. In some areas arsenic occurs naturally. The first thing to realize is that as these filters become saturated with a specific contaminant, they let more and more pass thru. If you can't detect it and don't know how much is in the feed water, you can't be certain that any filter is doing it's job. While free chlorine and many odors are easily detected and removed, many organic chemicals require varying degrees of long contact with high activity activated carbon and are not easily detected. As the system flow goes down contact time (and effectiveness of the activated carbon) increased. This is another advantage this system has over those that are pumped to a high pressure by an impatient operator to get high flow for a short time. To reduce growth of organisms in the filter, organic particles must be excluded by placing this after the bacterial particle filter, or it must be cleaned frequently. One activated carbon filter worthy of consideration because it combines small size and unusually low flow resistance with very small uniform pore size and high capacity is a polyolefin bonded powdered activated carbon briquette with a surface area of 2,200,000 sq ft and a pressure drop of .9 PSI at 1 GPM sold by Cole-Parmer as cat # E-01508-93 for $26. The Anetek CDC-10 is an alternative (1.3 PSI @ 1 GPM). An alternate approach adds the ability to remove some fluoride, lead, cadnium, mercury, and arsenic with hydroxyapatite charcoal. The granular blend, called R1022, is a more general purpose activated carbon and can be cleaned so it can be used as the first prefilter but it requires more attention than the above briquette. Without reactivation, it's life is less than the briquette. It is available in 80 cubic inch packages from The Rockland Corp. as stock number 8111 for $18.20. Each package should be able to treat 1/4 GPM. See the section on useing this media. I think everyone useing city water should have this at home since it has good removal propertys and good life at no increase in price.


    Selective ion exchange resins are useful to remove metals such as lead, cadnium and mercury which may be introduced by mining or pesticide use. One problem with these is that they have a poor shelf life, requiring annual replacement.Catalysts are available without this problem but they are expensive.  Another problem is that they can support growth of microorganisms. This makes these materials most suitable for applications requireing small ammounts of water regularly where a known problem exists. If you want to pursue this, here are two sources:

 (1) Western Water International manufactures Aqua Space Compound filters useing "patented, certified NASA technology". 7715 Penn Belt Dr., Forestville, MD 20747  301-568-0200

 (2) Seychelle Environmental Technologies, Inc. Seychelle water filtration products are the most tested products in the world using EPA and ANSI/NSF protocols.  Their primary goal is to make water safe to drink that is contaminated from suspended pollutants, microbiological, toxic chemicals from industry and agriculture, heavy metals such as lead, copper, mercury, and radiological contaminants. CONTACT:  970-920-6500,  714-361-6655, or email:icd@rof.net




   Since the energy required to filter water is proportional to the pressure, it is desirable to use a low pressure for a long time rather than a high pressure for a short time. I can think of three reasonable ways of producing moderate pressure for a long time: (1) Continuously operated pump powered by motor, human or other power source. (2) Pressure developed by gravity from water stored above the filter outlet. (3) Gravity developed pressure amplified by a hydraulic ram. The first case is great if you have electricity or the filtration system is large enough to keep a person pumping continuously. A hand operated piston force pump is efficient and easy to use but is not commercially available. Would someone like to make some? For an electric pump, a diaphragm pump operating near it's maximum pressure is efficient and reliable. The two that seem the most suitable are made by Flojet and are now sold by J.C. Whitney. Stock # 81JZ4553W costs $39.95 and is dvertized as pumping 1.1 gpm @ 35 psi while useing 3.5 amps @ 12 volts. Stock # 72JZ8421A costs $49.95 and is advertized as pumping 3.3 gpm @ 35 psi while useing 7.0 amps @ 12 volts and could be suitable at 6 volts pumping 1.6 gpm. J. C. Whitney is not known for accuracy and I have not checked these specs. The best small diaphragm pump is the Shurflo 8009-541-236 (COST ~$80) which is a good match for 2 #1040 elements when operated at 12 volts. Specs are .75 GPM @ 30 PSI & 2.8A, 5000 Hr brush life; .65 GPM @ 50PSI & 3.5A; 60 PSI max. In the second case, if the water is naturally available at the desired height, connecting a pipe to it is all that is needed but this will usually be the case only when small ammounts of water are needed or when the site is chosen to suit the water source. When only small ammounts of water are needed it can be carried up to an elevated reservoir and allowed to flow back to the filter by gravity, pumped up by hand if you have a suitable pump, or a reservoir such as a 5 gallon bucket or dromedary bag can be hung from a tree by means of a pully and rope, the water poured in at ground level and hoisted to the desired height. I don't like this solution because I am worried that someone will drop the bucket.  For example if a height difference between the middle of the input resivour and top of the receiving resivour is only 10 feet and a single 1040 filter is used with the suggested cleaning schedule and a 20% initial loss of capacity is assumed, 10*.433*13.85*(1-.2)= 48 gallons per day or 2 gal/hour could be produced. If the bucket is used, the filters and tubing can be stored in it. Whenever a resivour that may run dry is used, atleast one of the filters should have an air vent to remove the air in the lines when it is filled.


    The third solution, a hydraulic ram, is very nice for taking water from a mountain spring or stream or spring but needs to be adapted to the site, requires some care in installation and an abundant source (which is not unusual). The major components are reverse flow input screen, (a 20 - 30 mesh screen seems sufficient to keep the valves working smoothly), supply tube if needed, stand pipe if input tube is used, rigid drive pipe , overflow valve, check valve and air tank to cushion the output. While I do not have detailed data and have not done any testing, it is reasonable to expect a cheap but

well installed hydraulic ram to increase the total head by 6 to 8 times the head seen by the ram with an efficiency of 50%, greatly reducing the number of filter elements required. For example a 2" ram set for maximum production and having a 10 foot drop from a 30 gpm source thru a 40 foot drive pipe could deliver 2.3 gpm or 3300 gpd at 30 psi (at the pump output) which is sufficient for distribution to a small network or atleast 6 1040 elements in paralell. A single 1" ram useing 4.5 gpm under the same conditions would produce about 420 gpd useing a single #4 filter under reasonable operating conditions (280 gallons for a 16 hour day). Here are some design ideas for these pumps: The supply tube and stand pipe should be as large as practical inorder to deliver the available head to the pump, the drive pipe length should be 3 to 6 times the head. For input flows near the minimum, the drive pipe should be near the maximum to store more energy in the pipe, for flows near the maximum the drive pipe should be short to reduce frictional losses.  The drive pipe must be rigid, the ideal material for the drive pipe is steel but it is  most commonly schedule 40 PVC. Some have thought that PVC should be avoided due to the environmental impact of producing and disposing of it. I think this is well founded but the alternatives must be considered. A PVC drive pipe would be the largest use of PVC by a large measure but the alternatives are steel or a radially glass reinforced plastic. The overflow and check valves are somewhat matched because they must work together. The trip point on the overflow valve (and resulting pump output) can be adjusted by adding or removing weight from the poppet. The check valve should have an opening back pressure of around .5 psi. Efficent operation requires the pump to be rigidly mounted. Clamping the check valve outlet to a bracket which is mounted to a couple of large rocks or stakes would work. There are several choices for the local storage tank which must be closely coupled to the check valve. As the number of filter elements being fed increases, the minimum size of this tank increases. In all cases a vertical 4" pipe of suitable length can be used. It needs a port on top to inject air (a tire valve and bycycle pump is good). Since air is disolved in the pressureized water, occasional air additions will be required. This can be avoided by installing a flexable bladder in the tank. A suitably sized innertube could be put into the tank. If used, it must be folded, producing stress points. To prevent problems a large tube with a small enough ammount of air to prevent excess stress at the folds is required. For short term use this is probably not worthwhile but for a permanent instalation it is a real convenience. For pumps driving 1 - 2 filter elements, a tank can be made from a 2" pipe the bladder designed for the purpose availavle for $24 from the Ram Co. can be used. The specialized parts shown below are available from the Ram Co., 247 Liama Lane, Lowesville, VA 22967, 800-227-8511. The PVC check valve below may work better than the brass one, the poppet tees are overpriced and available locally. The maximum fall into the pump is 15' and the maximum practical lift above the pump outlet is 11 times the input fall.



      GPM        PVC      Brass      housing           cap        poppet

1"   1-5   RP10LVC $18.88 $19.75  RP10WVH $10.65 RP10WVC $5.46 RP10PF  $11.71

1.5" 2-10  RP15LVC $23.54 $27.55  RP15WVH $13.12 RP15WVC $6.59 RP15PPA $18.63

2"   3-30  RP20LVC $31.58 $35.50  RP20WVC $15.30 RP20WVC $7.70 RP20PPA $18.63


size complete pump  The complete pump prices may have changed. Also it is not

1"   RP10000 $108   certain what air tank is used. The tanks with the Ram Co.

1.5" RP15000 $139   bladder are too small for systems using more than 2 filter

2"   RP20000 $175   elements and are a bit questionable for the 2 element case.


                             SIZING EXAMPLE


First decide how much water you want. Lets say you want 50 gallons over 12 hours or perhaps in a 24 hour day but only attended for 12 hours, which is reasonable for a medium kitchen without many neighbors. Now lets say you want long term life for the filter in any condition rather than high immediate output. (You could rework this for good output with clean water input.) My asumption means that you want to use the #1040 element. If you look at my chart or table, you see that if you clean the filter when the flow reaches half the new clean filter value and allow for another 20% loss as explained in the article, the minimum instantanious flow will be 3.7 gallons/12 hr day at 1 psi or 5.6 gallons averaged over a cleaning cycle. If the water is clean and the pressure low, the time between cleanings will be long so the 3.7 gallons is used, realizing that you will usally have more. Then you can guarantee the 50 gallons from a single #1040 element if the pressure is 13.5 psi which you can get from a 31 foot fall. This is reaching the practical limit of what a manually fed system could achieve so you may want to consider the options:


1. Are you comfortable with this fall requirement. The answer depends on

   who is useing it and the terrain.

2. Require less peek water production, you always have the option of

   cleaning the filter early to meet the occasional peek demand.

3. Change to a #1700 element and get the same output with a 20 foot fall.

4. Put 2 #1040 elements in parallel and get the same output with 15.5' fall.

5. By useing a large receiving tank (in this example  32 gallons is

   sufficient) and providing continuous input from tank or spring, the

   operating time is increased to 24 hrs/day and peak demands are leveled out.

   Then the average flow in my table can be used with confidence provided the

   filter does not require cleaning overnight. Then the 50 gallons per day is

   obtained with a head of 2.3*50/13.85/.8= 10.3 feet which is three times

   better  than the initial design above. It is also much more convenient to

   mannage one large tank than many 5 gallon buckets (though you could put a

   few buckets together - in series for the output or in paralell for the



                             CLEANING THE FILTERS


The sole advantage of a cleanable filter is longer life and reduced operating cost. Wastful cleaning will eleminate this advantage. Katadyn supplies a cleaning tool they call a brush but is realy a rigid (curved to fit the filter) very course abrasive which will take off a large ammount of ceramic. If this tool is used, the advantage of a cleanable filter is largely lost. I do not know why they have provided this tool for these filter elements, but the approaches they used in some versions of their pocket filter are much better. I estimate an increase of life of five times or more when using the method I describe here as compared to the Katadyn "brush". (I have used water pressures of 30 PSI or less in my work while the Katadyn KFT filter can operate as high as 112 PSI which might drive the contamination slightly deeper, so my method could require modification when used with the KFT filters under some water conditions. Some users report that my method has worked well on there KFT.) I estimate 75 cleanings for the LPK1700 and 300 for the #1040 element when Katadyn's recommended end of life point is used, but this will vary somewhat depending on the nature of the contamination.


    The first problem is to know when to clean the ceramic filter. With a continuously pressurized or gravity powered system never clean the filter if you are producing sufficient water. If you are not, measure the flow and compare it to the flow graph. One approach is to match the measured flow to the instantanious flow on the graph and read the average flow. If these numbers are lower than you would like, clean the filter. Ceramic filters in the home made bottom opening housings are best cleaned by disconnecting the outlet tube, inserting the protective plug to maintain the cleanliness of the element's

interior, remove it from the housing, install the protective cap, IMMERSE the element in water and clean. Filters in 2.5" housings need not be dismounted for cleaning. If the element is not discolored, if it is shiny, or if it is slimy the first step is to brush it with a bristle brush. The bristles should be similar to those in a medium softness flat bottomed tooth brush or a very short bristled paint brush. This is to remove the surface slime. If it does not remove the slime it is too soft and if it removes a noticable ammount of ceramic, it is too stiff. Do not use a stiff scrub brush because it will gouge the soft ceramic. If a suitable brush is not available, a fine nylon scouring pad with little abrasive may be used. See the parts list below. In every case, GENTLY brush the ceramic as uniformly as possable with an abrasive pad. The common Scotch Brite abrasive pads used for cleaning kitchenware will do but Niagra light duty scouring pads are easyer to use for in some cases because they are less abrasive. If there is a dark deposit on the filter, brush it until the easily removed discoloration is removed. If the surface is not darkly colored it is probably covered with slimy microbes. In this case it is hard to know how much cleaning to do. There is no point to an incomplete cleaning but excessive cleaning is a complete waste of the ceramic, so start with slight cleaning with the abrasive. The best indication of the ammount of ceramic removed during cleaning is the color of the wash water. The best check on the quality of the cleaning is the flow rate after the element is reinstalled. Make the measurement after the filter has passed 1 gallon of water to insure that the air has been purged. If the flow is less than expected, clean more throughly next time to se if that is helpful. Deep contamination will reduce the flow and not be removed by normal cleaning, so if a little more cleaning has no effect on flow, take that as the clean filter value for future reference. To reinstall, rinse the neck of the element, remove the protective cap, insert the element in the housing, rinse the neck, install the nut or tube fitting on the vilter element (IMPORTANT - TIGHTEN THE NUT OR CAP, DON'T TWIST THE FILTER ELEMENT with much force. The ceramic is not very strong.) remove the protective plug, purge the air from the filter (optional), allow some water to flow thru the filter, and install the outlet tube. The 1 micron pleated media filter is readily cleaned of large particles but not necessarily of small ones or of biological slime. To attempt to clean the filter, connect incomming water to the outlet and connect the inlet to a drain, introduce air into the filter housing till it is about 2/3 full of water, invert, turn on the water and shake. (Clearly the prefilter housing is connected by flexable tubing and easily moved. The other filter housings are best held rigidly.) If this cannot be done, the next best method is to remove the element from it's housing and agitate it along it's axis while submerged. If these filters are to be cost effective, they must be effectively cleaned.


    The powdered AC filters must be placed after the bacterial filter to prevent clogging, it should be disinfected by passing 3% hydrogen peroxode through it before useing if it has been unused for over a week.


    The granulated AC filters should be constructed so they can be disasembled for cleaning. The media can be poured into hot water and simmered for atleast 20 minutes. This provides partial activation as well as removing particulates.


                              MORE USEFUL PARTS


Pressure guages, In normal use pressure should not exceed 70% of full scale.

60 PSI, 1 PSI grad 2% accuracy 1.5" dia 3847K2  $7.21  from McM

30      .5         2%          1.5      3846K3 $10.53       McM

15      .5        cal @ 5 psi    2              $4.00       WR


Flexible pvc tubing, easy to use for short lengths such as internal plumbing

and runing to a near by container, can pinch off but lower pressure tubing

is more durable when pinched off.

1/4"ID 3/8 OD 36 PSI max @ 73 deg 5233K56     $10/100 Ft   McM

1/4    3/8    75           73     62501       $.13/Ft      WR

5/16   7/16   30           73     5233K59     $13/100 Ft   McM

5/16   7/16   46           70     FK-06405-09 $8.75/50 Ft  CP

3/8    1/2    26           73     5233K63     $15/100 Ft   McM

3/8    1/2    41           70     FK-06405-12 $9.75/50 Ft  CP

3/8    1/2    50           73                 $.20/Ft      WR

1/2    5/8    20           73     5233K66     $20/100 Ft   McM

1/2    5/8    28           70     FK-06405-18 $13/50 Ft    CP

Silicone rubber, Durometer

5/16   7/16   10   50 A    70     5236K14     $.73/ Ft in mult of 5' McM

5/16   7/16  >10   70 A    70     5236K69     $.73/ Ft in mult of 5' McM

2"  .066 wall 80 psi  polyester reinforced, lays flat until pressurized,

                      easyer than rigid tubing to carry

                     5295K35 $.67/ft < 100 ft, $.55/ft >95 ft, mult of 5'  McM

3"  .078 wall 70 psi 5295K39 $1.12/ft < 100 ft, $.93/ft >95 ft, mult of 5' McM


1 micron pleated polyester prefilter, 6 sq ft area in a

              9 3/4" x 2 3/4" dia cartridge             45235K43 $5.85  McM

Powdered activated carbon briquette, polyolefin bonded with 2200000

      sq ft effective surface                          E-01508-93  $26  CP

Katadyn 1040 element                              $90 post paid in USA  Leh

                 (Better prices may be available, contact me for current info.)

Katadyn 20743 element                 $75 post paid in USA               Leh

                 (Better prices may be available, contact me for current info.)

PVC holder for 1040 element from 2.5" pipe, includes air vent and 6" outlet

              tube with pinch off clamp, element mounting nut, press on

              cleaning cap, mini wash bottle                        $20  WR

    For screw on quick connect mounting adapter for more secure

    outlet hoze connection especially with outlet pressure above

    5 PSI, specify 1/4 or 3/8" hoze connection                  add $3   WR

  Nut only for your own holder                                      $3   WR

  Cap with 3/8" FPT outlet only, for your own holder (mounts filter

      element to holder and provides 3/8" FPT outlet)               $6   WR

PVC holder for 1700 element from 2" pipe, includes air vent and 6" inlet &

    outlet tube with pinch off clamp, screw on quick connect mounting

    cap (provides quick connection to 1/4 or

    3/8 hoze (specify which))  & cleaning cap, mini wash bottle     $12  WR

  Cap with 3/8" FPT outlet only, for your own holder                 $6  WR

Multi element assemblys useing these holders and pressure guage can be made to

    order, specify circular (up to 6 elements for carying in a bucket) or

    linear (with it's own housing and optional empty position for post filter)

Bulk head connector, suited for mounting a tube to the bottom of a bucket

    1/4" hoze barb $4, with holder for prefilter or screen          $9  WR

    3/8" hoze barb $5, with holder for prefilter or screen          $9  WR

    1/2" hoze barb $4.50, with holder for prefilter or screen      $10  WR

Life guage - a flexable tape measure (Katadyn suggests the end

    of life is when the diameter is 1.5" but if there are no thin spots,

     a low pressure system can use them a little longer. If you find any

     micro cracks in the filter element, you reached end of life.)  $1  WR

Cleaning pan, Don't forget to have something to clean the Katadyn elements

    in. It is best to lay the filters horizontally partially submerged when

    cleaning but a 5 gallon bucket would do.

Source Codes:

McM  McMaster-Carr Supply Co., POB 4355, Chicago, IL 60680  708-833-0300

CP   Cole-Parmer Instrument Co., 625 E. Bunker Court, Vernon Hills

     IL 60061                                               800-323-4340

Leh  Lehman Hardware,POB 321, Kidron, OH 44636              330-857-5757

RC   Rockland Corp, 12320 E.Skelly Drive, Tulsa, Ok 74128   800-258-5028

WR   Wayne Robey, 215 S. 6th St, Lafayette, IN 47901        765-742-7850


All prices subject to change without notice, prices marked WR are only intended for those participating in Rainbow gatherings since this is a not for profit undertaking on my part. Others may enquire. Shipping is additional unless otherwise indicated. I can supply any parts listed herein but for additional shiping charges which will vary with my inventory.


                                          revised 08/8/99 by Wayne Robey