2 months ago I moved my 90 gal reef after it was up for 2 years (removed all sand, rock and 10 gal of old water-reassembled tank). Water is a brown color, doesn't look like diatoms. Nothing growing on rocks, sand or glass. Water is 78 deg., 0 nitrate,0 nitrite,0 ammonia,8.4 ph. Using RO water and instant ocean-1.019 salinity. Only 20 blue hermit crabs in tank, want to clean up water before adding fish...