Hi, i have a 90 gallon reef tank with a sump. In the sump a have a protein skimmer and 150 phosban reactor. I've had this tank for a year now and im having a lot of problem with my ph. It's so low i can't raise it. Tried a lot of things but nothing has worked at all. Don't know what else to do but love my tank. Looking foward to chating with you guys. thank you and have a good evening.