Java and peacock moss do well with excel. I overdose the tank and the mosses dont die and they are healthy and growing. I bough fissidens fontanus and I still use excel, i use precautions when I receive new plants so, I now using excel in normal concentration, it doenst kill or do anithing to the fissidens but doesnt help fissidens. the fissidens is growing normal. The excel in very high concentrations kills all moses (I kill some java and peacock in a glass with 50% excel to get rid of algae) and it can kill another delicate plants is high concentrations. If you have a big tank you not will notice that the excel do anything wrong but in small tanks or in experiments glasses 
the excel can kill.
the excel can kill.
