[Edward]

Originally Posted by LilLou

Now my question is with larger fish (namely Discus in my case) should we lower the amount of NO3 we are adding to the water? Or a least be testing weekly to check on the levels till we get everything perfect?

Lou

You don’t want to lower KNO3 dosing with discus. Fish waste is organic and plants can’t use it in this form. Plants use inorganic nutrients (KNO3, …). Unfortunately, test kits probably measure both as one. So dose as usual and test for NO3 occasionally. If it goes over range then partial water change can correct the levels. I also recommend using TDS meter for watching the discus water deterioration.