I have a heavily grown out 180 gallon tank with a 60 gallon sump. The corals are predominantly SPS/ acropora with large brain and hammer corals on the bottom. My problem is the calcium and alkalinity demands result in trouble maintaining a dkh above seven. I have an MRC c-1 reactor with a panworld-10 pump for internal circulation and a peristaltic pump driving the system . The effluent flow is 100 cc/ min, and I've lowered the pH to 6.2. I would hate to start supplemental dosing. Any adjustment advice would be welcome