I'll try that ph test tonight. If it is due to high CO2 in my apartment, an airstone in the sump wouldn't help at all though right? The only reason I'm freaking out is because all my corals have been shrunk up for a over two weeks now. Not even my zoas are out. I did two 50% water changes this week but that didn't help. I replaced all 6 T5 bulbs in March. I have carbon in a reactor in my sump. If its not the low ph, and all my other parameters are ok (except for the high alk which was caused by the buffer), what else would be making them shrink up?