So, came home from a little vacation and found my glass caked in what I can only imagine and figure is alk that had precipitated out from the water collumn. After I scrubbed what i could off of the glass, I found the entire tank is covered in this crud!! The sump has it caked in there, the sand, the pumps, everything. I did a 30 gallon water change on it last night and dosed 50ml of vinegar before and after the water change, so my alk is under control, for now. But how do I get rid of this caked up, powdery crap?!