Ted’s Fishroom

Water in the Fishroom

(This page was originally written in the Fall of 2005.)

     Water quality is the most important factor associated with maintaining healthy fish. Everything else in the fishroom can be perfect, but if the water quality is bad there is no point in even trying. When I talk to people about water quality one of the most common misconceptions that I address is the idea that all water quality problems can be solved in the tank. This is simply not true, unless you are blessed with a tap water source that has zero hardness and a low pH. Most water sources are not low in hardness and low in pH, however, and the aquarist working with tap water either has to take measures to make the water from their source usable, or only keep fish that are happy with the conditions of the water out of the tap.  The water that comes out the of tap has the following parameters (approx.): 550 mS (225 ppm TDS), pH 7.9 and 16 KH. Not to bad if I were keeping rift lake cichlids. The biggest problem is the high KH.

     My fishroom is designed to be able to accomodate any type of fish that I want to keep. If I am at a store and see some awesome chocolate gouramies, incredible Lake Tanganyika cichlids, and a Xingu River pleco I just have to have, then I want to know that I can buy them and the water parameters I need at home will be available. There is only one way to do this, in my opinion, if your tap water has even a moderate amount of general and carbonate hardness. I have a 110 gallon/day reverse osmosis unit with deionization capability. My system makes water with 0 conductivity (0 mS / 0 ppm TDS) and 0 carbonate hardness (0 KH). My water is as pure as I can get it without using a research-grade distilliation machine. Here is my unit:

     I purchased my unit from Spectrapure about four years ago. I have been using this company’s equipment since the late 1980’s when they were the first (that I noticed) company actively advertising reverse osmosis systems to aquarium hobbyists. I have been very happy with the equipment I get from them, though they are a little more expensive than some of the units available through smaller companies and on Ebay. I trust SpectraPure will be around if I have any questions though.

     This unit has a standard set of prefilter stages. The first is a sediment filter and the second is an activated charcoal filter. When I first got to the house and set up the unit, I ran water through directly from the city water line.   The sediment filter turned bright red in less than 200 gallons of water!  That bright red color tells me that there is a lot of iron in the tap water. Plants like it, but soft-water fish do not. 

     I have two reservior systems for the water that I make. The first is a 30 gallon barrel that I use to store and heat pure reverse osmosis water. The second is a 150 gallon vat that I use to mix and store reconstituted water. This system allows me to make water in batches that differ chemically. My Central American cichlids get water with moderate hardness and a neutral pH, my ‘difficult’ apistos and other acid water fish get water that is low hardness and very acid pH, and my West African cichlids get water that is very low in hardness and a neutral pH. When I get some hard-water rift lake cichlids I will be able to mix water specifically for them as well.

The RO barrel is positioned above the vat so that I can siphon water from it while I am mixing. The RO barrel has an auto-shutoff float valve that allows me to turn the RO unit on and not worry about the barrel overflowing. Filling the barrel takes about eight hours, so I usually let it fill overnight. The lid on the barrel has a center hole through which I have threaded the electrical cord for a heater. The heater is suspended in the water.

Water in the larger vat can be circulated by using the refill pump that is plumbed to the bottom of the vat. I use a hose with pvc valves and fittings to refill the tanks. The pump is plumbed inline, though I could use it as a submersible pump. The pressure from the pump is good for the fishroom, but I also use it to fill a 110 gallon tank on the next level of the house (1/2 a story up… we have a tri-level), and the presure is not high enough to fill it quickly. I plan to get a larger pump sometime soon. There is a heater suspended in the larger vat as well, but I need to circulate the water for it to heat thoroughly.

I used 1/4″ tubing and pressure fittings to make a tee off of the RO/DI water line into the larger vat. I put a ball valve on the end of that extra line so that I can turn the RO water going into the vat on and off. The vat is never entirely empty because the intake to the pump is not on the bottom of the vat. When the pump runs dry there is about and inch of water left in the vat. I usually do not use an entire vat to do a series of water changes, leaving the vat about 1/4 full. It takes about 24 hours to fill the vat from the low point to the 100 gallon line.

When I mix a new batch of water, I start with the vat full of mostly RO water at the 100 gallon line, then add RO water, tap water or aquarium salts depending upon the water parameters I want. If I need a higher pH along with hardness I add tap water. If I want the hardness but not the pH buffering carbonates I add salt. If I mix the hardness too high, I add RO water from the barrel. It is not an exact science. How do I determine what the water’s parameters are? Easily… with this:

This is a Hanna Instruments Combo meter that instantly measures electrical conductivity (mS and TDS) and pH, as well as the temperature. The meter will also automatically adjust the parameters for temperature differences, so I can test the warm water in a fish tank and compare it to the cooler water in the vat and know that the hardness and pH readings are accurate. A meter like this cannot test for carbonate hardness. No hand-held meter of this type can measure KH. This is because carbonates are poor conductors of electricity. KH will register on a conductivity meter if it is really high, but you cannot accurately determine the level that way. A color-change test kit is used to measure KH.

My Hanna Combo meter is the most-used tool in my fishroom. I use it every day, several times a day. I have had this meter since the Fall of 2003 and have used it almost constantly in my fish tanks and in my teaching lab when I was a biology/chemistry teacher. I have not had any problems with this meter, and I have not even had to change the batteries yet. The only part that should wear out is the pH electrode, but that is replaceable at a fraction of the cost of a new meter. If you are interested, this meter is available through the stock shop.

My water supply system is probably the part of the room I am happiest with. The system works perfectly for my applications.