Yea its really weird.. And veeeery frustrating.. And copper/ ich X is not reviving them from whatever it is..iv lost everyfish i come home to snails dieing.. I didnt go cheap on anything stocking.. 15 nassarius snails 12 scarlet red crabs 4 skunk cleaners.. Koran angel, kole tang, powder brown tang , ocelaris clown, six line wrasse, 90+ lbs of fiji / bali LR.. 2 high power hydor powerheads brand new bioballs( added during cycle which cycled empty for months since i have so many other tanks there was no rush) the only ONLY thing i can think would start to do this is this is my first time with a overflow/sump system and when the water dips low the part of the sump that was wet leaves a salt/grim kinda deposit on the sump wall that kinda floats off when i top it off during my water changes ( everysunday) im at a loss this friday i plan on moving everyrock back to my 75gl ( depending advice from all you if maybe my rock caused this) and the selling this tank and going with a different..