I did my normal cleaning Wednesday on my 75gal. clean the filters,glass,10 gal. water change. When I added the water I noticed my corals did not look happy and this morning it looks like they are all dead or on the way out. I have never had a problem until now, all my perameters are good the only thing I changed was I used Kent reef carbon instead of Marineland and I opened a new bucket of salt (the same I have been using ) . The fish seem to be ok but all the coral mostly softies look very bad. I also noticed that my skimmer cup is filling up ten times as fast and the odd thing is it is way more clear than normal. My R/O D/I unit only has about 250 gal. through it so I would not think thats the problem. Could there be something in the salt or carbon that we don't or can't test for? Working nights but will change carbon back to Marineland and and new filters when I wake up. Any thoughts ??