7% bidaily - Testing the Water Change theory... please give this judgment

[fishfin]

I always use NITRATE test kit to base how much water change to do, after a few times (month) you should know how much to change.

 

[shekes]

There are sooo many threads on WCs and I always encounter the same mistake:
People believe that 2 small WCs are the same as one big one.
Now here is formula I copied without permission:
"The waste in the tank on the evening (after a WC) of the first day = W(1-WC%)

Waste in the tank after second day (after WC) = W(1-WC%) + W(1-WC%)(1-WC%)

Waste on third evening = W(1-WC%) + W(1-WC%)(1-WC%) + W(1-WC%)(1-WC%)(1-WC%)

Etc., etc.


In English it means the fish are constantly putting out waste and it is being partially removed every evening with the water change, so the waste builds up over time. It is shaped like a learning curve where it is steep at first then gradually levels out to a nearly constant amount (the time to level out (flattening of the curve) varies with the WC% but is around one week for most of our situations). The actual curve if done by hours would actually form a sawtooth pattern but still in the general form of a learning curve."

For a more exact info click here

If you have difficulty understanding, you can do the following experiment:

Take a bottle of milk and perform small WCs on it. Try pouring out 7% as suggested by OP and refill with water. Shake and repeat. Shake and repeat. Shake and repeat. Shake and repeat. Shake and repeat. Shake and repeat. Shake and repeat. Shake and repeat. Shake and repeat. Shake and repeat.

You'll see that it will take you a whole damn day to get the water in the bottle absolutely clear. If you pour all the milk out at once and refill with water it will take a few seconds.
Therefore the WC is a trade off between a big one that stresses your fish and a small one than stresses the fish-keeper.
Not thaaaaat complicated really.

 

[hardb0iled]

Are Nitrates the only harmful component of the aquarium water that accumulates over time and can cause the fish harm?

 

[danny boy]

no but in the main they are. the ammonia is the worst thing for the fish but your bacteria converts that anyway. although im not 100% sure i think really its only the nitrates thaat you need to remove. as was said earlier one poster found the right amount of plants to convert the nitrates so water changes wernt needed, although the water not evaporated somewhat that may have become an issue as you do need to replenish water with vital minerals ETC

 

[shekes]

Somewhere there is a thread on nitrates & plants and stuff. But it was really complicated and people never agreed on whether or not plants remove nitrates from the water. I spent quite a bit of time trying to understand it and ended up going back to changing water.