melting plants

Hi all, I have a 54 bowfront natural tank that's been running for nearly 2 years. All was going well. Then I saw this white patch on my clown pleco and thought it might be columnaris. I treated the whole tank with furan 2 and kanaplex. I didn't know that the meth blue in the furan was bad...

Hello guys. These are the specs for a 10 gallon tank I planted. I am having problems. Need help. Substrate- Nat geo black substrate. Fine Light- T8 flouroscent Plants: Amazon sword, Java moss, Hydrilla, Dwarf Hairgrass. No CO2 injection or fertz yet. My plants are melting and it has been a week...