That the polyfilter hasn't turned is encouraging. Give it another few days. Run some carbon.
The problem is, it may also have killed the microscopic bacteria in your sandbed and rock. It may NOT, however, have reached below the surface, so bacteria will start re-colonizing the upper layers of sand and rock.
Treat it as a new tank, one in which you unfortunately already have fish. You don't say whether you have a filter on this system. But start testing for ammonia and nitrate, and have some Amquel on hand in case you get an ammonia spike. Feed lightly, and try a couple of snails. If they survive, add more snails/hermits until you have one per gallon. I am assuming you have 1 lb sand per gallon and 1 lb live rock per gallon: sand is somewhat optional, but the live rock isn't. Advise us if this is not the case and we will devise a plan.
Wean it slowly off the filter if this is to be a reef. Filter ok if this is fish-only.
Keep adding to this thread to keep it active and post your general parameters and tank description for more help.