I have been having a problem with my 90 gallon planted tank. It is going to be used for discus (not for a while). The problem is the plants are slowly dying off. Got T-5 lighting H.O. 2-10000K that are on 12 hours a day and a very large peace of drift wood. The substrate is some natural gravel that is very small (60+lb) and 15lb of floramax. I pulled out a clump of mondo grass and the roots are rotting. What is going on. Last thing I have well water the Ph is 7.8ish out of the tap and very hard with lime and calcium. The test kit for hardness said 200+.