I currently have 6 tanks, 1x 125g, 1x 110g, 2x 75g, and 2x 40g. All my tanks are planted, and all have PFS (pool filter sand) as substratum, except for the two 40g, which have bare bottoms as I use them as QT tanks (but have plants too!).
I do weekly water changes, ~ 75-80%, together with...