I don't have a test kit yet though I know how to do it:) I am getting it this weekend. My question is hypothetical. If I were to test and got good readings, do I still need to do a water change? If so, how much. Thanks!

It all depends on the readings...

As long as Ammonia is 0... Nitrite is 0.... And Nitrate is below 20ppm then No, you do not need a water change...

BUT keep in mind the lower you keep your Nitrates the better... So you could still do a 25% W/C and that would be just that much better!

a few years back, i used to set up aquaponics...having plenty of plants
in the tank... i did not make any water change for 17 months... i just refill
the take to make up water losses due to evaporation..... and all my fish
survive..... now if your nitrate doesn't exceeded 20, then you can do
without water change..but must refill the water loses to avoid dry spell

I do water changes at the regular scheduled times regardless...the only difference would be if I noticed higher water readings and then I just bump up the volume a bit.

johnnyphoenix wrote:


Spot on johnny same as me..

I do a wkly water change, no matter what the readings, lowing nitrates can only be beneficial to the fish and I find a schedule better than here and there changes.

but as nicki said if your nitrates are 20 or lower you can leave it a little longer. if you have ammonia/nitrites you don't have much option other than daily water changes to keep them as low as possible until the filters bio can handle the toxins

If your nitrates are low enough then you dont need to do a water change. But you will then will have to continually retest until the levels are such that a water test is needed. Far easier to get into a habit of a weekly water change with one test before it to make sure you are doing enough!!!!!

Also the lower the nitrates, the better