Curling leaves and stunted new growth is a co2 issue, respectively.
I had this happening to my Bacopa Australis. Some new leaves were stunted, leaves rolling under and even some were completely rolled up. I was like what the heck! I was told Calcium as well but had plenty of that. Increasing co2 slowly helped fix the issue. Drop Checker is always yellow. Made sure fertilizer were good.
GSA is an indication of too much light. Raising the light up like you did should help with that. As well as less demand for co2. Though maybe a slight adjustment with co2 may be a good idea. Just finding that balance.
Best of luck