First thing: take your water to a pool store and get it tested. You can re-order r-0013 from Leslies on-line or TaylorTechnologies. Buy a BIG bottle to use and store.

Raise your FC to shock level. Since you don't know your CYA, aim for 12-15ppm. Start witha gallon and a half of either regular or ultra bleach and see where that gets you. Plan on holding your FC up there for 48 hours and see if that fixes your problem.

That's just my firstline suggestion.