Hi, my tank has been a fallow tank for 3.5 weeks after brooks breakout. I’ve been changing the water still to keep the tank going but the nitrates are still supper high. I just have the CUC. The Hanna Nitrate reads over 75.0 even after the water changes. Any ideas on why there’s still so much nitrates when the tank doesn’t have any fish? Tank is 2yrs old, 20g high. GSP is doing ok.