Water changes with Discus?

Question

I've had my Discus tank up and running for about 2 months now. I was told by breeders and other discus experts to do 25% weekly water changers. I have a 55 gallon tank so I am taking 10 gallons out each week.

To me this seems like quite a bit. Wouldn't it start a new cycle each time I do a water change? I have a fluval filter and 3 packages of the Biomax balls, so is this why it doesn't start a cycle each time?

I've had fishtanks for about 10 years now, but until recently, I've never did any water changes or knew much, if anything, about water cycles. Could somebody help me out on this?

Also, since the biomax balls carry all of the beneficial bacteria, wouldn't it make sense to never replace them with new ones? Fluval recommends changing it once every 3 months, staggering the replacements. Is this just a way for them to make money? I don't see why I should replace it.

Thanks for any help!

I'm probably overthinking on this one. Its just that I spent $300 last night on 3 discus and they will be arriving Tuesday morning. I'd hate to loose that much on these fish so early in the game for something stupid that I didn't ask.

Answer 1

Doing water changes has little affect on the bacteria once the tank has cycled. The bacteria live in the filter media (in this case your bioballs) and attached to the gravel. There's very little of the cycling bacteria that would be in the water. You do need to remove the ammonia and nitrite if the tank is cycling, and the nitrate if it's finished, though. All of these can be toxic to fish if the levels are high enough, it's just that for nitrate, it takes a lot more to be harmful. It is a plant fertilizer, though, so removing and replacing 25% of the water keeps it from "fertilizing" any algae in the tank. The replacement water also contains some minerals (calcium, magnesium, sodium) that are used by the fish and any aquarium plants, so doing a water change replenishes these.

The basis of cycling is bacteria that use the ammonia that your fish produce as a part of their wastes as their energy source. Since ammonia is toxic to your fish in relatively small amounts, this is a good thing! By using it for their energy, they convert it to nitrite, which is also toxic. A second group of bacteria uses the nitrite as an energy source, and they convert the nitrite to nitrate, which the fish can live in in larger amounts. Unfortunately, there aren't tank bacteria that use the nitrate, but live plants will use some. The rest need to be reduced through water changes.

You're correct that the bioballs are one of the areas where the bacteria live. But these also collect a lot of debris from fish poo, plant leaves, and maybe some food that gets caught in the intake/overflow. These will decompose and become a source of ammonia themselves. So this is what you want to clean. You can rinse them in a clean container of tank water, or dechlorinated water and reuse the same ones. So, partly they do make money if you follow their directions to the letter. You can also reuse filter pads in hang-on filters as well, even though the directions on those packages tell you to replace them.

Answer 2

You know what, I would change to a biowheel filter.
The biowheel instructions say to never ever ever! replace the wheel.

But I mean.. If it says to replace the balls then I guess you should? That doesnt make very much sense though, like yuo said. If you want, try changing one at a time. That way, you dont mess up the bacteria cycle and have ammonia spikes.

See, how the cycle works is..

The bacteria and ammonia released by your fish reach an equallibrium. As long as the amount of fish in the tank doesnt go up suddenly, everything will work fine because theres just enough beneficial bacteria in the filter to cancel out your fish's ammonia. You can actually change 90% of the water in your tank safely, because the bacteria isnt in the water. Its in the gravel, the filter and the bioballs.

If you're unhappy and feel like giving up on the bioballs, introduce and biowheel filter and remove one set of bioballs per month. Eventually the biowheel will be able to support your whole tank. As long as you get the filter with the large enough wheel.

And agh! Youre so lucky. Ive wanted Discus for forever but was never sure enough of my fish-keeping abilities. Good luck man!

Answer 3

It doesn't start a new cycle because the bacteria's in your filter and not in the water. But if the new water you introduce contain high concentration of Chlorine or Chloramine then you will face a new cycle. As the chemical will wipe out your bacteria. But normally the chlorine and chloramine isn't that concentrated and they get further diluted by the 75% volume of water, moreover you do add water conditional before you add in the new tap water :)

As for the Biomax bio-ball the only problem would be if they are coated with waste, if you rinse them with tank water you could probably reuse them. If you're using something like Biomax ceramic rings you probably have to replace them once a year as you can't really clear the waste once the spores gets choke with waste.

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Answer 4

In a sense you are removing some of the bacteria that breaks down the waste but you are also removing the waste along with the bacteria needed to cycle. So when you put in new clean water there is stil bacteria in the tank and filter and as the fish produce more waste more bacteria builds up to handle it. Thats why it isnt really cycling again, it is staying in equilibreum as someone else said above. Its not like when you change the water the only thing your removing is the bacteria needed to breakdown the waste, you are more or less removing more waste than the essential bacteria. So you will end up with a cleaner tank with more essential bacteria than waste. I hope this makes sense and helped give a better understanding as to why water changes are very important.

Answer 5

I don't think you need to worry. Certainly not that bad.