This thread uses an airstone and co2 scrubbers to lower co2 and increase pH.CO2 scrubber without skimmer
Skimmerless CO2 Scrubber Build I'm writing this build thread for a CO2 scrubber setup without the need for a skimmer since I had a difficult time finding anyone who had done this. The plumbing is simple: air pump --> CO2 canister with sodalime --> an airstone placed in your sump or tank I...www.reef2reef.com
I JUST read through that yesterday!
He updated it at the end to say it had very little effect on larger tanks (I think his original tank was a 90?).
I started dosing kalk and my pH is much better now. I also started a refugium. The combination should work pretty well for me.