40 gallon breeder. Filstar XP, half sand, half red flourite, driftwood, stones, planted, CO2. Water parameters, all normal PH-7.2-7.2, Nitrite 0, Nitrate 20-30 ppm, ammonia 0.25. For the record, I've never been able to get ammonia to zero, even after a 50% water change. Tank has been fine for 2...