Water ChangesWater Changes
Part of your filtration system consideration depends on how often you are willing to change the Discus' water. Even with the filtration setup explained (Filtration section) with a 75 gallon tank, I find it necessary to vacuum/change at least 25% of the water twice a week. The water doesn't become cloudy, but the bottom is so full of feces and old food stirred up when they forage around, that it should be changed. After all, Discus are cichlids and they're, for numerous reasons, dirty fish. I've had people (even one breeder) tell me they change as much as 50% of the water daily!! Sounds like quite the hassle and traumatic for the fish unless you have pre-treated and temperature correct stored water. Many Discus keepers do keep the fish with no filtration system at all, depending totally on water changes!! Your water changing requirements will depend largely on your filtration system and the fish load (and plants or lack thereof) in your tank.
At least 25% twice weekly is commonly considered to be a good rule of thumb for most Discus tanks. Again, this all relates to the number of fish, size of the tank and filtration system.
Water changing is required for the Discus' general health, but regular changes are extremely important to avoid stunting their growth! The experts often elude to the fact that they've seen full grown Discus at only 4"-5" from neglected water. Healthy Discus, depending on breed, with regular large water changes will often grow in excess of 7"-8". Considerable debate constantly goes on about the importance of water changes, but the general consensus is that it is definitely important for the Discus' health and growth.
If you have a large tank or multiple tanks, and are tired of the "bucket brigade" you will surely want to consider getting one of the water change valve/hose systems like Python offers. They hook up to your sink, you vacuum the bottom off into the sink, flip the valve and fill the tank back up. Then just treat the water with chlorine eliminator and also adjust the PH for the new water added. Don't get careless or in a hurry with this, since the fastest and most common way to stress them is with a fast PH change. I've read many horror stories about weird things happening with discus that eventually were narrowed down to a quick radical PH or temperature change.
The optimum setup for the keeper and the fish is to keep a separate container for water changes. Any type of container like another aquarium, a barrel or a water storage tank will do. The idea is the chlorine will be removed by just setting there for 24 hours, the PH can be adjusted quickly (without worrying about shocking the fish) and the container can have a heater, just like the fish tank, to keep (or bring it up to) the aquarium(s) temperature. Obviously, you need to have some type of pump/hose arrangement to make this work. Submersible pumps are available for less than $50 for this purpose. You can also use muriatic acid to more inexpensively lower PH in a setup like this (see PH section). You can't use such chemicals in the fish tank itself. As you may have found out already, it can be a pain to you and the fish, as well as expensive to keep the PH low enough for Discus if you change water often. I use a 55 gallon plastic barrel. Make sure, if you do this, that you fill (let sit for awhile) and empty this type of container a few times to be absolutely sure it's clean. The drum I got was supposed to be absolutely clean, but when I filled it, left it sit for a day and just tasted the water, it was gross (tasted like soap or something). Just be very careful, at first with your new water container. After that, you and your fish will be very happy you chose to store and pre-treat the water exactly to match the tank(s)! Not only is it more convenient, but you can make large (50+%) water changes without shocking the fish, in case you have a disease problem and need to do so. One more advantage is that it's very fast to complete your water changes. I vacuum and add about 35-40 gallons in a half hour! No messing around adding water adjusting chemicals after you change the water.
Reverse Osmosis (RO) and Deionized Water (DI)...
Many areas have tap water that is much too hard for Discus. They are also sensitive to heavy metals and many other chemicals that may be present in your tap water. RO units remove these chemicals, cleansing and softening the water as well as lowering PH. They may seem somewhat expensive, but many swear by them and in some areas, are definitely necessary. You need to calculate your cost for reducing PH and take into consideration how bad your tap water really is. Deionized water systems filter the water through resins that also take everything out of the water and lower the PH. Necessary trace elements must then be added to the water for the fish with both systems. (RO-Right, Electro-Right, etc) As with many Discus-related items, they have definite advantages and disadvantages (and myths and differing opinions). If you choose one of these systems, you don't necessarily have to run all the water through them. Any additional cleaner and softer water is better than none. Many people use 50% - 75% RO (or DI) water. I find, with my tap water conditions, a mixture of 75% RO and 25% tap water produces PH about 6.5. With a touch of baking soda, I get some buffering capacity and PH at about 6.8. I use a Kent Maxxima unit, which is an RO unit with a DI canister as the final filter. My 75% combination still produces pretty soft water (40-50 ppm) Some Discus keepers will tell you they would use 100% RO/or DI water. If you do this, you must add trace elements back to the water (RO-Right, Electro-Right, etc) It depends on your tap water condition before you treat it. I don't do it (100% RO) because my RO/DI water comes out at the bottom end of the hardness scale and I need to add chemicals to harden it, so I just use 25% tap water.
Don't be concerned with using the softer water with young Discus. They actually do fine in harder water until they are nearly adult. Most agree softer water is necessary if you wish to try breeding them as they mature. Also, I don't hear many good things about trying rainwater as an alternative, with acid rain and bacteria considerations. Bottom line is.... get a hardness test kit and see what you have! Anything between 100 and 180 ppm (medium to slightly hard) is generally considered fine for mature Discus (if you don't use RO or DI). Mine is only around 50 and I've had people tell me theirs do fine over 200, so... as usual, go figure!
UV Sterilizers...
You may want to consider using one of these water sterilizing units. Water is pumped through an Ultra Violet Light unit which kills nearly all water-borne parasites, viruses, fungi and bacteria. The advantage is obvious. If your fish become stressed, they won't become infected by waterborne parasites. If you choose to use one, use the following formula to determine the wattage of your UV light. Take the amount of water pumped through the unit per hour, in gallons, and divide it by 25. Example.... For a 75 gallon tank, you could pump 100 gallons per hour through the light, which, when divided by 25, would indicate you could use only a 4 watt UV light (which is the lowest wattage usually available). If you're a serious keeper, you may want to consider using UV as further insurance/protection for your fish. 4 watt units cost less than $75.00 I consider it a good investment and a good way to gain a little more peace of mind, especially if you have a lot of them in your tank. You can also be less stringent as far as quarantining new ones, since your water is "sterilized". Fish can still become infected from others, however. Think of it this way.... If you were in a sterile room and someone sneezes in your face, you could still get their cold!! Same idea with a UV sterilized tank.
UV lamps lose much of their strength in about 6 months and must then be replaced, in order to function properly.
If you use a UV Sterilizer, be aware that you must turn it off during use of any medications . Also, do not turn it back on until all medication has been removed by the use of carbon and water changes! If you turn it on too soon, the meds may be chemically broken down into toxins which can harm the fish and fowl the water. A good idea would be to wait a couple days extra after you think you've removed medication from the water to return your UV to service.
From what I hear, the only disadvantage could be..... The fish may become accustomed to this type of water and if you discontinue use or transfer them to another tank or a friend or other owner without UV, they could more easily become infected, since they may have become unaccustomed to their presence. (If anyone has info to the contrary, please let me know)
I've had absolutely no disease problems with my 20 + Discus since I put UV on my tanks in March of '97. I think it's a great investment and cheap added insurance, since it only costs a much as a couple good fish! If part of your fun with Discus is the challenge of fighting disease and stress related ailments, don't do UV. However, if you have a life (family, work, etc.) you might wish to consider UV! Purists may consider this a bit of a "copout", but it's made my Discus keeping much more fun and definitely less stressful. Less worry about moving fish to other tanks, adding new ones, using nets between tanks, slight temp and PH changes, etc. Slight stresses don't seem to cause as many problems. This is not to say everyone needs UV, but if you've experienced more parasite, bacteria and viral problems than you wish to deal with on a regular basis, it's a good way to help the situation and therefore not become discouraged and quit the hobby. It certainly does not take the place of good water changing and filtration habits/procedures, but may give you more time and desire to dedicate to these required basics! If you only have a few Discus and have minimal problems, don't bother with UV. I have more than 20, with substantial investment in time and money, so I find much more peace of mind with it.
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