HC DSM Plants browning and slow growth

[kadium]

I started this tank a a few months back using DSM. I had too much water at first and had high light and grew lots of BGA. So after treating the BGA I let the tank get drier and leave a small opening in my tank to let air/moister out. The humidity has been from 70-90% with the opening. My lighting is 2x 24" 24w 6700k lights with excellent reflectors. I only use one of the bulbs daily now, for photo period of 8-12 hours. Sometimes less. The growth has been very slow and the leafs are starting to brown. I really want to just fix it and keep moving forward. It's been over 5 months of dry start.