I have a 30 gallon tank with 20 gallon sump. Total water volume about 30 full gallons because of rock and sand. I have SMR-1 with pellets and my Nitrates are still 30+ after a good month or more on pellets. Nitrite and Amonia is 0 not worried about PO4 because this is a FOWLR tank. DO I maybe need to add more pellets? WC are 5 gallons every week like clock work Craig