You are very welcome.
Coral is made from saltwater inverts, what else? What it leaks is pretty much the same soda....
You don't really need mesh bags, old stockings would do. (But filter bags can be found at most lfs for $1-$2).
Rinse the corals before using. Add slowly, I'd say add about a teaspoon of corals per day to the bag. You don't want pH to jump too fast, this is dangerous to the fish. Watch pH. Continue adding slowly every day until your pH is close to neutral (7).
Notice that your pH=6.0 may actually mean pH=5.0 or anything, 6.0 is probably the lowest reading on your kit.
It is hard to interpret your readings without knowing the kH. You either have a cycle running very badly because of low pH, or you don't have it all... I suspect that you do, otherwise ammonia would have been higher. The way to know is to check your nitrate reading: if you were using a strip, 0 is unreliable, it may easily be 10 and the strip would not show. If you have non-zero nitrates, you have a cycle going, and raising pH will solve the problems quickly; otherwise you are still for a couple of weeks of pain.
Yes, overfeeding may lower the pH by using up the buffering. Limit the feeding to one flake (one bloodworm) per fish for now, your fish will be ok.
If plants are decaying, remove dead leaves, or everything, if they really look dying.
Put some live floating plants if you can. Specifically, water sprite is potent.
Good luck!
