Originally Posted by
dspeers
Thanks much for the info. I am just a little amazed/disappointed that there was a noticeable difference between a 1 vs 4 day interval given the measured nitrate level and no intrinsic filtration that would selectively reduce nitrates. On the basis of what I have read, I had it seems erroneously concluded that Nitrates would probably be a good test absent any chemical or biological filter impacting the level and that < 15 was safe for even juvenile discus. For my grow out 45 gallon (bare bottom, foam filters), my tentative plan was to check nitrates daily and change 50% whenever the level went above 10, unless Ph and/or ORP was changing more rapidly. I found that approach intuitively appealing as it would take into the account the variable waste production due both age and number of fish. Did you happen to check Ph as well? Your info certainly does validate the approach that indicators should increase water changes but not decrease.
The plan I noted prior is for my display tank, which will have adult discus and plants. How often do you do water changes in your adult discus tank?