Most of us who have kept aquariums for a while have been changing water for as long as we can probably remember. Whether we have, in fact, done so with the least amount of stress to the biomass in the tank remains to be seen. Changing water appears to be a simple process, and it is. But some precautions are necessary.

Large water changes stress the fish and invertebrates more than small water changes. Such should be pretty obvious because large water changes alter the water chemistry more than small ones. Large water changes = sizeable change in water chemistry = stress = may cause parasitic outbreaks.

If the amount of water to be changed is small, which is likely if you perform regular 4 to 5 percent a week, or 2 percent every couple of days, you will not need to set up an elaborate hose evacuation system that runs to your sink. A small bucket will usually do just fine. Use a hose with a ½ inch internal diameter and while removing the water, siphon out some of the detritus that is lying on the bottom of the tank as well. Such will benefit the overall water quality in the immediate, and if done regularly, as is suggested, will increase your redox potential slowly but surely in the longer term.

Regular water changes can be used to slowly lower the nitrate and phosphate levels in the aquarium, providing the makeup water does not contain nitrate and phosphate itself. We have already explained that you must check the water you use, pretreat it and chemically filter it, and make sure that the salt you are using does not contain nitrates and phosphates either. Although you may find these comments to be repetitive, I have done so on purpose hoping that the remarks will really sink in, and that you will from now on check all additives you use to prepare water for your tank, including the water itself on a regular basis.

If you are using a trickle filter, as we hope you are, add the new water to the sump of the trickle filter, not to the aquarium. In this manner it will mix more evenly with the main water body and create less of a change in the tank's water layers. Stability of all conditions is important, as pointed out several times already as well.

Often it is the attention paid to such small details that will make the difference between an aquarium that runs well, and an aquarium that looks in superb shape. Please remember it and tell your hobbyist friends about it. It will help them too. If you share with them, they will share knowledge with you, which in the long run helps everyone in the hobby.

Automating the water changing process introduces an even greater degree of water chemistry stability, as it can now be done on an even more regular basis, for instance once, twice, or several times a day, depending on how much water needs to be changed. The equipment needed to do so is not expensive and is easy to acquire, as we shall see in the next paragraphs.

The only issue that you need to deal with is the evacuation of the excess water as, when you add new water to the tank, you will have to remove a similar amount for the tank not to be overfilled, and possibly overflow, especially after a few days. The following situations can exist:

INSTALLATION WHEN A DRAIN IS AVAILABLE:

Run a piece of large diameter flexible hose from the fitting placed in the hole in the filter to the drain you will be using. If no fitting is installed in that hole, glue in a hose barb of at least 1" internal diameter. Hose barbs can be obtained from hardware stores and plumbing supply places. Tighten the hose down with a clamp. Glue the barb in with silicone glue, or a similar compound. Resin based bonding agents will make for a stronger bond. They are available from just about any hardware store. Most of them are 2 compound based, and are sold in separate tubes or plastic dispensers in a blister pack.

INSTALLATION WHEN NO DRAIN IS AVAILABLE:

Place a powerhead in the sump of the trickle filter, or in the tank, and attach a piece of flexible hose to the output side of the power head pump. Plug up the air intake hole of the power head. If you donUt, water will be pushed out through that hole back into the sump, or tank. Such is counter productive, so close off the hole. In line with the electric wire that is normally plugged into a wall outlet, install a float switch that activates the pump when the water level rises above a certain predetermined position or height. As you now add water (we shall see a little later how this is done), and the sump or tank level rises, the float switch will activate the power head, this will evacuate water, and the water level will go down again. See the section on float switches for exact wiring instructions of such devices, earlier in this book.

INSTALLATION OF THE WATER CHANGING EQUIPMENT:

Prepare a vat with reserve water. The larger the vat, the longer the supply will last and the less frequently you will have to refill the vat. If it is rather large, for instance 10 gallons or more, you should sink an air stone in the vat and run the output of a good air pump through it. This will make the water in the reserve container circulate and reoxygenate itself.

Determine how much water you will need to change a day. For example, if your tank is 100 gallons and you wish to change 5 percent a week, you will need to change 5 gallons divided by 7 (days of the week) every day. Thus the same in ounces, is 128 times 5 and then divide the result by 7.

This works out to 91.5 ounces per day, or around ¾ of a gallon per day.

This is just an example, and you must do a similar calculation for your own tank. Set the timer you are using to make the water changer operate to its minimum setting. Because of the short span of time that you will want the pump to run, you should use a timer that allows for very short interval settings. Radio Shack makes such a timer. Its minimum setting is one minute. It is part of their Micronta range of products.

You must now regulate the output of the pump so that it delivers about ¾ of a gallon per day each time the pump goes on (at least that's the number needed in our example. Use the number that you calculated for your own tank), and decide at what time of the day you want to perform the water change. Set the timer for one minute "on" time and adjust the output further if necessary. If the amount of water that you need to dispense cannot be delivered in one minute by the pump that you are using, increase the "on" time progressively until you reach that level. In most cases the amount of water that you need is small, and any power head pump should be able to do so in one minute or less (therefore the adjustment of the powerhead's output). If not, tighten a small clamp placed around the hose attached to the output of the power head to reduce the output even further.

Lastly, you must dispose of the water that is evacuated by the powerhead/float switch combination, so the filter or tank does not overflow. The hose attached to the powerhead's output side can be guided to a sink, or if no sink is available, to a vat that can hold a sufficient amount of water for you not to have to empty it every day.

Ideally it should hold the same amount as the reserve vat itself can hold. If such is the case, you can then empty one vat (the one that holds the evacuated water) and refill the other one (the one that holds the new salt water) in one and the same session, which makes for a more organized maintenance schedule.

Automatic water changers can always be installed on a system, whether you have holes in the filter or not, whether you have a drain available to you or not. Some installations are a bit more involved than others and require more equipment, but installing such a system can always be done and will not cost an arm and a leg. At the time of this writing a float switch cost around $65.00, the Micronta timer around $25.00 and the powerhead around $20.00, or a total of just over $100.00. look through catalogues from scientific supply houses for other float switch and timer offers as well.

W.W. Graingers, McMaster Carr, Whitney, and others, all offer a wide variety of equipment that you may want to consider, if not for this application, at least for some other one that you are considering. When it comes to reef aquarium technology you are no longer limited to supplies available at your local pet or hardware stores in your area. Because the variety of equipment that you may need, or can use, shopping around is strongly recommended.

Vats can be obtained from large hardware stores, from swimming pool places, from D.I.Y stores, from businesses that sell fiberglass molded vats, from catalog mail order companies, and so on. The whole setup should cost less than $175.00, which is really a good deal, considering how much easier an automatic water changer can make your life, and how beneficial it is to the stability of the water quality and chemistry.

Should you set the water changer for more than one cycle per day? All depends on how much water you need to change. If only a small amount is involved such will not be the case, but if you have a real large tank, and you are changing several gallons a day, you may wish to split the changing over two or more cycles. The decision is entirely up to you and a factor of the quantity you are changing.

Remember, whether water changing is done manually or in an automated fashion is not the important matter. Doing it, and doing it regularly, is what really counts.

Because automating the system reduces the amount of manual work that needs to be performed to do so greatly, I recommend that you seriously consider setting such an automated system up.

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