Select Aquatics of Erie, CO.
          Creating an Automatic Water Changing System
                             for Your Fishroom
            *No Drilling of tanks!



                 This is an Automatic Water Change System that Requires:


               No Pumps

               No drilling

               No Air

               Little Maintenance


         Because of this:

             You never need to risk breaking a tank to drill it.
             Moving tanks around is no problem.
             System can be modified easily to add or delete tanks.

          This system will not:

              Pass water between tanks
              Spread diseases or pathogens

          Water being added is:

              Proper temperature
              Evenly distributed between tanks

          However, the system requires:

              -Being gravity (siphon) dependant, tanks must be at least 12” off ground.

              -You will need a nearby sink to both fill and drain, OR a reservoir and a drain
                holding temperature controlled, aged water. (Where you will then need to
                pump the water from the reservoir)

              -Using water from the tap will work without dechlorination, as you will only
                be adding up to about 20% tank volume at a time.

             -Obtaining and Working with PVC and PVC glue


              -No drilling tanks, leaking drain portholes, pumps, motors or moving water
                    with air or powered means that can fail
              -No need to turn anything off or disrupt fish to change water
              -No need to add dechlor
              -Can do changes regularly, at any percentage, as often as you like
              -What used to take me 3-4 hours on Saturday of carrying buckets
              I can now do daily, with no effort, in 40 minutes.
              -Temperature shock is avoided with frequent, small changes
              -You can spend more time cleaning tanks and doing other work
              -No backflow siphon issues
              -Water does not mix between tanks
              -Fish are healthier, bigger, and breed more frequently.
              -Plants do far better
              -Periods of inactivity (vacations, etc.), are less stressful on
              the fish because water changes continue.
              -Diseases are far less frequent (I may have had a case of ich once
              in 5 years, and nothing else).
              -Though I cannot drain water from individual tanks with the system,
              I can easily fill whenever I clean by turning on that zone for as
              long as I need manually. I can turn off the other tanks in that zone
              if I do not want to change any water.


              -If you need to empty a tank you must still do it by hand
              - You are committed to the water parameters that come from your water supply.
              unless a tank is taken off of the water change system, it must do well at the pH
              and hardness of your source water.
              -At times there can be a fair amount of working with PVC glue
              -Tanks must be observed regularly to restart a drain siphon if it stops
              -You should be aware of internal water pressure within the PVC system
              (Do not turn water on full when valves are open if water is turned off
              into tanks.)

              Changes made to my fishkeeping to best adapt to the system.

              1. My fishroom is primarily bare bottomed tanks. The system does not
              clean up mulm or vacuum the bottoms of tanks

              2. Most of my fish are well adapted to the water quality that comes
              from my tap. My Ph is about 7.4, Hardness is low, at 90ppm.

              3. I am experiementing with doing a 4 minute change daily, rather
              than 10 minutes every other day (which equals about 15% in 10 gal. tanks 
              from my tap).

              4. I am not concerned when they are occasionally overfed, but have strived
              to keep the bottoms free from mulm buildup. However, water changes can be
              frequent enough to prevent ammonia buildup, encouraging the cultivation of
              infusoria for fry- so I leave a thin layer of mulm in my fry tanks
              (particularly the smaller egg layers). When a tank appears stressed,
              I first look at temperature, knowing that water quality will less likely be
              a factor.

              5. Whenever I do any work that involves draining a tank more than an inch or
              two I always ensure that the drain siphon has not stopped working.


               Materials needed for installation:

               Pad and paper- everything is written out before hand

               A 2, 4 or 6 zone control box and sprinkler valves - depending on the size of
               your room, that are available at any Home Depot, Lowe’s etc. A lawn sprinkler
               control box costs about $30, and a valve for each zone is about $10.

               System can be done entirely manually with lines splitting into separate zone
               lines from sink, and changes are then done by turning on water by hand, rotating
               from zone to zone. You must be sure to have a zone open when turning the water on,
               and open next zone before turning current zone off so that PVC setup isn’t forced
               to hold entire tap water pressure (though it should be able to).

               PVC- get to know the guys at Home depot. They will wonder what you are doing after
               buying up all their ½” valves half a dozen times. Your planning on paper will tell
               roughly how much PVC, fittings and valves you will need. PVC materials are bizarre
               cheap. 10 feet of half inch PVC costs under $2.00.

               You will be using ½ inch PVC tubing (for all filling lines), ¾ inch (for all drain
               setups from each tank) and 1 inch section lengths that will collect water from the
               tank drains and connect to the main sink drain.

               I highly recommend at least one hand-held PVC cutter (about $10.00).

               PVC glue- I just use the simple clear stuff in the gold can. Use your own judgement.
               You MUST glue all fill lines, for they hold pressure from the tap. I don’t glue most
               drain lines once the water has drained from the tanks, and I prefer knowing it can be
               torn down or changed easily, but I do encounter occasional dripping. However, drain
               setups at each tank MUST be glued until the water gets to the main drain, or air will
               get into the setup where it should not, and the siphon can stop. PVC glue runs about
               $2.50 a can.

               Angles, Ts, Valves etc.- Each tank’s fill and drain line setups will require a certain
               number, then multiply out. They are also affordable- “contractor” packs- packs of 10-
               are also generally under $2. Valves are the greatest expense. Each tank has one, and a
               few more valves will control where water goes based on the size of your setup. They run
               about $3 apiece. As a rule (depending on your room) you’ll be using 90 degree pieces
               in ½”, ¾” and 1” sizes. Also connectors, tees, and end caps and in all three sizes,
               reducers will be 3/4” to ½” and 1” to ¾”, but you will only using ½” valves. Again,
               try to determine how many you will need ahead of time to keep visits to the hardware
               store to a minimum.
               Electrical Ties- I use these to help hold and stabilize the lines against the racks
               and each other. 8 or 11 inch ties work best, and they can be connected to one another
               to create longer pieces if needed. Bags of 100 are about $9.

               You will also need:

               About a weekend to do this, depending on the number of tanks you have.
               A ventilated area
               A drill with a 16th inch or so bit
               A Tape measure
               2 pairs of pliers to easily disconnect joints not yet glued
               Clothes you don’t mind getting wet, and possibly stained with PVC glue.

               Best way to do it:
               Be aware that it will be 1 week after building this system before being able to use it.
               The PVC glue must be fully cured and dissipated before water running through the PVC
               cleans off the glued joints. Introduced water pressure will move any glue residue into
               the tanks with the fish. I have lost fish that died as a result of my running water
               into a tank through a line containing new glue that hadn’t dried thoroughly.


               1. Ensure that all tanks are where you want them to be. Have tanks placed to provide
               easy access behind them, and set up in straight lines when possible. The bottom tanks
               must be at least 12 inches from the ground and above the drain used to collect the water
               that drains out.

               2. Build all of the drain setups for each tank from ¾’ inch tubing. Observe attached
               drain siphon setup photos. Keep in mind the size of the tank each will be used on,
               and where the main drain line will be located that it will be draining into. All fill
               lines will be ½ inch and drain lines ¾ inch. You want to be sure that water never fills
               faster than it can drain. All drain lines collect to a 1 inch line so that it will not
               back up.

               You will see that where the drain T is placed within the drain setup apparatus determines
               the water level in the tank. Always keep at least 2 inches “headroom” from the surface of
               the water to the top of the tank to prevent overflowing if the drain setup loses its
               siphon (from having worked on the tank where it was drained down, etc.)

               I built one for each size of tank (all 10s, 20s etc.), didn’t glue them, took them each
               back apart, then made each piece multiplied out to number of tanks. Then I put them
               together and glued them, then set aside.

               The most time intensive part is drilling all of the little holes into the in-tank drain
               ends so that any fry are not sucked out.

               The connection where this drain setup drains into the 1” drain line will NEVER be glued
               into the 1” line. You will need to use this joint to restart the siphon if it stops.
               (which happens very rarely- maybe once every other month on one or two tanks in my 60
               tank fishroom, and can always be traced to my working on it or it being drained down
               too far, and I didn’t check it afterward)

               3. Now build the ½” fill lines for each tank. Drill a 16th inch hole into the middle of
               each end cap. Each fill PVC line must be made specifically for each tank. Keep in mind
               where the light sits, so that water flows into tank unobstructed. I use the white plastic
               honeycomb light grating to cover tanks that need to be covered, they don’t obstruct water
               flow from the fill lines.

               Do not make them so that drilled caps sit in the water, water should enter from cap
               ideally 2-3” from surface to provide aeration and prevent back siphoning into other
               tanks when the flow stops.

               4. Glue fill line setups together, keeping knobs so that they are easy to access and
               knobs can move freely from open to fully closed.

               5. Begin to conceive where the ½” fill line from the sprinkler valve back at
               the sink will be placed, and how the fill line will best lay against the back
               of the tanks and attach to the rack, while next to the drain setups.

               -I installed my fill lines first, then had the drain sit lines against them. See
               attached top rack PVC photo.

               -Keep in mind that the fill lines will hold pressure, so keep turns, etc. with
               the fill lines to a minimum.


               Keep in mind that everything you do until step 10 will be disconnected and
               re-built outside or in a well ventilated area to be glued together in sections.
               The sections will then be be glued together in the fishroom as they are put in
               their final place on the tanks.


               6. Lay out 1” drain line tubing behind tanks and begin to put in the 90 degree
               angles etc. to fit the lines to the angles of your room.

               -There needs to be a 1” line for each row of tanks that will then drain into
               the single 1” line out to the sink drain.

               -Temporarily attach this line to the rack, or support it as you will want it.
               (Nothing will be permanently attached until after everything is glued in a
               ventilated area and brought back to the fishroom. I do not glue the 1” drain
               lines, so they can be roughly put in place.)

               -If you are really organized and somewhat good at this, gently slope the 1”
               drain line toward the sink drain from far point of the room. This will help to
               avoid any standing water within the setup.

               7. Determine how you will tap into the sink drain line.

               I put a “Y” piece in below the fishroom sink so that both the sink and the fishroom
               water go out of the house together.

               In one fishroom, instead of draining to the city sewer I drained into a plastic
               garbage can with a pump that then moved the water out into the yard and garden.

               8. Run the fill line from the sink to the sprinkler valves mounted nearby.
               Hook valves up to control box.
               Have fun and be creative with all the new PVC you just bought, and end up with a
               line from each valve to a designated portion of the fishroom.

               9. Hang the already made drain lines from the tanks.
               The tanks of each row will drain into their own 1” drain line that will then T
               into the 1” line that goes to the sink drain. Put a tee into the 1” line, then
               you will need a 1” to ¾” reducer to connect the ¾” individual tank setups into the
               1” line. Do not allow a tank to somehow drain into a tank below. Each tank row drains
               into the same 1” drain line that goes down to the main drain line and out to the main
               drain. This will prevent water mixing between tanks. (This can be seen on photo of back
               of tanks, attached)

               To prevent vacuums within the 1” drain lines from developing, causing siphoning to start
               where it is not intended, I put a T into the lowest 1” drain lines with an open ¾” line of
               PVC rising straight up to above the room’s water level, allowing air to enter the drain
               lines as they head to the end drain. This opens up the flow, prevents siphoning and helps
               keep water from building up within the drain system. In my room of 6 zones, I have put in
               4 of them spaced equally throughout the room.


              10. Begin cutting tubing for both fill and drain lines that will be connected to already
              built fill and drain setups and put it all together. Build as it will be in final form
              with light hoods placed in, etc. Do not glue anything yet.

              11. Divide up when finished into sections that can be brought to a well- ventilated area
              to glue. Obviously, keep all angles of each connection as it should be- I have used a marker,
              putting a line over the joints that needed to be angled, then simply matched them up when
              outside. Completed drain setups can be left on tanks, they will never be glued into drain
              lines for they need to be disconnected to start or restart the siphon.


              PVC glue and its fumes are toxic to fish. Always allow any freshly glued area to dry
              thoroughly- days, not hours, before running water into the tanks from newly glued areas.

              12. Glue sections together. Let dry and air out THOROUGHLY. Keep all valves in the open
              position to assist air flow through the PVC when drying.

              *Nearly all of the times I have encountered problems with drain siphons has been due to spots
              I’d missed gluing at this stage of the process.

              Be aware to keep structure in small enough pieces when finally placed on the tanks in the
              fishroom so that it can be put together and glued easily, without any force or tension.

              13. Carry back into fishroom and place on tanks, aware of where sections need to be
              connected. Do one section at a time, make sure every connection is glued that needs to be
              when putting the system together. See attached back of rack photo.



              It is only PVC. As long as you have one or two connectors and a little glue you can cut a line
              (As long as the water is off. This may sound stupid. I’ve done it. More than once.) and change
              whatever you’d like. Put it back together and voila, good as new.


              14. When all is in place and glued marvel at your work and try to forget about it for at least
              3 days, a week is best. Leave all valves on tanks open to assist air flow through system.
              Then after a wait of 3-7 days…

              15. Make a “Siphon Starter”. Observe siphon starter photos attached. You will need two
              pieces of ¾” PVC, one maybe a foot long, the other about 18”. Connect with a 90 degree elbow,
              then put 2nd 90 degree elbow on other end of shorter piece.

              16. Start the siphon in each drain setup structure for each tank:

              To start the drain siphon loop for each tank: Be sure the tank is filled slightly above where
              the T in the drain setup will drain down to the 1” drain line. Gently connect the 90 degree elbow
              (because it will need to come off quickly) on the shorter end of your siphon starter over end of
              the line going down to the 1” main drain line. Place finger over hole in top of drain setup and
              inhale firmly to begin siphon in outer loop. Then connect to the 1” drain line placed to take water
              from that tank while trying to get as little water on your shoes as possible. See attached Siphon
              Starter photos.

              17. Now go around the room and check that all of the valves on the fill lines into each tank are
              open about halfway. ALWAYS be aware to keep system “open”. Closing off many or all of the valves
              could cause a crack or a blowout in the system over time.

              18. Now the fun begins. GENTLY turn on the water about 1/3 to half the strength you want to
              eventually expect to use.

              You are looking for:

              - Leaks, Drips

              - Water going where it should not. This sounds silly, but if you have more than 10 or 20 tanks,
              you may find that a drain line taking too many tanks too soon is causing another tank in an odd
              place to fill rather than drain. In my room of about 60 tanks I had two of those spots to fix.

              - How evenly is water being distributed? Begin to turn some fill valves up, some down depending
              on flow to adjust the flow into each tank. If no immediate problems, turn up flow of water
              slightly, continuing to adjust. Tanks closest to water source will be at greater flow than tanks
              later in line and tend to fill faster, etc.

              - Watch for some tanks filling faster than others. This could be water going in, but it is more
              likely that the siphon hasn’t started properly in the drain setup, and needs to be restarted.

              - Water flow from the nozzles hitting light hoods, causing any problems.

              - Watch for water going into tanks causing too much disruption, and adjust accordingly.

              19. Let it run for up to 10 minutes, possibly adding an antichlorine agent- you do not yet
              know how much water is actually being added. Gradually increase the pressure to the desired flow,
              watching for any of the problems listed above.

              20. Turn off. Then set timers at control box. I would keep the water changes gradual at first-
              I have been doing 15% every other day for 4 years (about 10 minutes on a 10 gallon tank with
              water pressure at about 2/3rds full strength.). At first, I would start at about half that,
              increasing as you wish, keeping in mind that too much can bring chlorine and chloramine issues.
              UPDATE- Since this article was written, I have since settled into a 15% water change daily.

              At some point you may want to find out exactly how much water is being changed. To do this I
              divert the fill stream from a tank at about mid distance from the sink into a bucket, measuring
              the amount of water in the bucket at specific time intervals, keeping track of where the knobs
              are placed where the water is turned on. Full strengh with both hot and cold turned up could
              end up too hot, and far more water than you need.

              Maintenance: This for me is simply looking for puddles, locating the leak and fixing it,
              usually by replacing or simply gluing the offending joint. As well, due to joints weakly
              glued initially or missed having been glued altogether, a drain setup will lose its siphon-
              in my room it will happens on one tank about every 3 months. Because the water levels
              in each tank are set where the "T" is placed going down to the 1" drain line, a 15% addition
              during water change will not overflow the tank, but can be spotted and fixed before the next
              water change.

              UPDATE- Since this article was written I have seen that the eventual loss of siphon on a tank
              can often be spotted days before it actually happens. But more often, I have had problems from
              turning off a tank to restart the siphon at a later time, (because I had drained the tank working
              on it, or it looked liked it needed to be restarted) and then forgetting about it- resulting in
              the tank going a period without water changes. So I have put a 1/4 inch strip of red electrical
              tape on every tank, marking where the water level of that tank is when the drain siphon is working
              properly. When a drain line begins to lose its siphon it will sometimes go gradually- over a few
              days, and the tape will show the water level rising in the tank. If it has been turned off or is
              not filling for any reason, the water level in the tank will then evaporate down.

              The room now has close to 1000 ft. of tubing. I have tanks from each zone spread throughout 
              the room (all 30’s fill at same time wherever they are located in the room, etc). This is simply
              because the system evolved over time, and I did not move tanks, as I probably should have, to
              accommodate the system. That is not the easiest, nor the most sane way to do it. Hopefully,
              yours will be set up more cleanly and less prone to the occasional repair. With my system of
              hundreds of connections and joints, I fix about 5-6 a year, usually in one or two quick

              On the rare times a drain siphon loses its siphon it is usually because I had worked on the
              tank and drained the tank too far, then forgot to restart the siphon. When this happens it
              will not drain- Obvious because the tank is fuller than the other tanks. (the reason for the
              “headroom” mentioned earlier.) If you are only changing 10% or 15% each change, then the 
              tank will not overflow.

              Sometimes a joint had simply been forgotten to be glued, and at other times it may just
              need to be restarted. Of dozens of weekends and vacations of up to a week away I have never
              had a siphon lose its siphon when I was gone.

              When I have had any problems:

              Over the 6 years of using this or a similar system, problems have been rare, but here
              is a rundown:

              1. A sprinkler valve once malfunctioned, and a section kept refilling and draining,
              eventually killing all of the fish in that zone. That was the single biggest disaster I
              have ever had. I now spend the extra buck and get better quality valves. There has never been
              another instance similar to that. Preventable.

              ***** UPDATE- When putting in the sprinkler controller, most will provide an option for a
              valve that will come on before zone 1 and turn off just before the last zone finishes. This
              way the longest a broken valve can cause the water to flow into tanks is the maximum length of
              time all of teh ziones you are using take to fill- preventing losses. Today I use that
              "master valve" setup, and would never consider the system being set up without it.

              2. Twice I lost tanks of fish to water changing too soon after a repair and fumes wiped
              out the fish. Not all fish were affected. In both instances 3 or 4 tanks were affected,
              but in both instances it was only the tiger limias that all died. Again, preventable.

              3. Twice I put water in that was too warm, but I was only changing 15%. I would never have
              known, except that in both instances I wiped out my A. toweri that seem particularly
              sensitive to warm water, while affecting no one else. Also preventable.

              And the last of those problems happened over 4 years ago. Good Luck!

              Greg Sage


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