Im not sure why but i let my tank go for a little because i didnt see a issue its been maybe 8 months since i started this tank and my ph wats yellowish brown and readin 7.5-7.6. I did another water change yesterday and it killed one of my sailfin tangs that was big. I have a hyger at the surface and now i just added a blower aimed to the top and took 2 of the 6 socks in sump out for water to fall in hole and break everywhere more. Im not sure wat eless i have to do. Anyone have help ? Everything is 0 except the ph …..