Fishkeeping Tips 9: Water Changes

    The limiting factor in keeping an aquarium, and certainly multiple tanks, is your ability to provide consistent,
    substantial water changes where water is removed and replaced from the aquarium. Topping off alone is not
    adequate- by doing so you are simply raising the concentration of toxic substances in the water over time.
    A minimum on a stand alone display tank is about 20- 30% a month, but about 20% a week would be best. Here,
    an automatic water change system changes about 15% of the water every day. Generally, you can add up to 40%
    of a tank's volume with tap water to an established aquarium without harming the fish- the chlorine concentration
    in your water may vary. Always make sure that the water you add is the same temperature as the water the fish
    are in, and it is best to dechlorinate the water if possible.

                                             The First Water Change System
    Begun in a modest form in 2000, the first water changing setup used PVC lines connected to a sink to the
    tanks that both filled and drained. It worked well, but became unwieldy after the room grew to larger than
    20 tanks. The siphoning of the tanks started automatically, and I could consistently control the amount of
    water going in and coming from the tanks. It is much simpler than the system that both fills and empties the
    tanks, and though it eliminates needing to use buckets and dramatically shortens the amount of time required
    to do water changes on your tank(s), it does require that someone is present when the tanks are fiiled back up..

                                                                      Here is that setup
    A 1/2" PVC line is installed from a sink to the aquariums(s). The PVC line follows along the bottom of the
    tank(s), and a "T" is installed below each tank so that a line goes up to and into each tank. A 1/2" PVC
    valve is installed at least a foot below the water line of its tank. The The PVC line would extend from the
    valve up and into the tank, extending below the water level to where the water is desired to be drained
    during a water change.

    The PVC tube that goes down into each tank is then capped at the very end, with holes (about 1/16th of an
    inch) drilled the last few inches, allowing water to both be siphoned out and poured in, without sucking
    adults or fry into the tubing. After a tank had been filled, the valve was turned off, and water was held
    in the PVC from the valve to the end of the line under water in the aquarium. When the valve was turned
    back on, the water would drain back out. In other words, a siphon had been created and held until the next
    water change. Simply turning the valve back on then caused the tank to drain back out. After the tanks had
    been filled with this setup, the PVC would be disconnected from the sink faucet for the next water change,
    and by turning on a tank's valve, the water from that tank would then drain out until air hit the holes in
    the drain line. The PVC would then be reconnected to the faucet, and the tank could then be refilled,
    turning the water off when the tank had reached the level you were looking for. Unlike the system described
    below, if you do not manually turn off the water, the tank will overflow.

       A pic of the first Water Change PVC setup.


    Each tank had one of these PVC lines going into the tank, extending down to about halfway into the water,
    so that each tank would drain down about 50%. When the tank drained down to where the holes drilled into
    the drain line began, air would enter the holes, and it would stop. The tank would then be refilled and
    the process begun again. It was great, but with multiple tanks filling at the same time a close eye needed
    to be kept on the process so that tanks being filled do not overflow.. Also, when replacing half of the water
    in many tanks, all in one session, it became necessary to stop midway for 3 or 4 hours to let the hot water
    heater reheat- or the last tanks simply got cold water, which would stun and possibly kill the fish. For
    simplicity with fewer tanks this is still a great way to install a water change system, but for someone
    wishing that the system des all of the work (except the initial construction), this next method is best.


               The Updated System (Fully automatic and for more than a few tanks)

    Al Wood (former chairman of the ALA) brought me a device made of PVC that would drain an aquarium
    from one side of the aquarium while it was being filled into the other side, and this new device did not
    involve drilling holes in the glass of any tanks. Over the next 4-5 years the system continued to be refined
    to where it continues to work today with no drilling of tanks and no pumps. Water can be changed at any
    amount, and as frequently as necessary. Changes of 15% per day can be done without concern for
    emptying the hot water heater, and it is all done on timer, automatically, so it is no longer necessary
    for anyone to be there when it is being done. Because less water is being exchanged more frequently,
    there is no longer any concern for draining the hot water heater. In this fishroom of 130 tanks it takes
    about 45 minutes to do a 15% water change on all of the tanks.
    The sprinkler system timer can be overridden easily when it is best to do the water change with someone
    present - otherwise the room is done entirely on its own. Below is a photo behind a small section of upper
    row tanks. A copy of the manual fully describing how to build and install this system, with information on how
    to avoid having water cross between tanks, is now available for download HERE. The only maintenance
    involves the very rare times when a tank loses its siphon, generally because a tank had been drained
    down to clean it, and the siphon had not been properly restarted. Also, joints that had not been
    adequately glued initially, or that have dried out over many years will develop a slow drip leak,
    which are easily repaired. Because there is no drilling of glass, tanks can be easily removed or added,
    and changes to the system can be done easily.


            Back to Previous Tips                                                                                    To Next Tip


             The current system with both drain and fill lines.







                 Home                 Contact Us                  Receiving Shipped Fish                 Keeping Select Aquatics Fish







 Setting Up

 Brine Shrimp


 Red Worms



 Vinegar Eels




 Water Changes



 Making Stands



 The Fishroom

 The Goodeids

 The Swordtails

 Plant Species



 Site Index

 Fixit Guide