Bleach is more than fine to use for cleaning the tank and accessories. Make sure you rinse it well and then rinse it again with a very strong solution of water + dechlorinator. The dechlorinator will neutralize any left-over bleach.
I doubt coraline aglae will do any harm in a FW tank. From what I've read thus far, coraline algae does need Ca and there's not that much in tap water, nor are there marine salts. Unless you have plants and are supplementing, most likely the algae will just die off.
pbrack:
Btw, a decrease in Ca will decrease the hardness, not increase it.
Roan