If you are following the EI dosing regime and doing the 50% water change weekly I would adjust a single variable. Keep the dosing the same - adjust your CO2 (as you have) and watch the response. Continue to adjust a single variable over time - I would personally use 1 to 2 weeks as a guideline for time.
As for the drop checker. Are you using aquarium water or 4dKH water? Have you checked the ppm of your CO2? I attached a link to a table that can help you determine if your CO2 is in line.
wow what ram species is that?! Those colors are amazing!
My LFS has called them "Electric Blue Gold Head Rams" and another time "Electric Blue Balloon Rams" and I've people tell me they are long finned rams... So I called them "Long Finned Balloon Electric Blue Gold Heads" haha... Only the one has super super long fins, they are about . I think hes the only one out of like the 40 they got in to have them. I had pick of the bunch thankfully.
I tore this tank down and started 2 new 20 Longs... one reef and one FW planted. The current house I have was just too big a pain to do big water changes every week with RO water and the winter made me slack on them.