I was curious about his system in the garage. Seems like that should have helped if it had good air exchange. Of course, the water flow in relation to the pH sensor would make a difference in his case.
I have two gyres pointed at the surface which gives tons of surface agitation in the frag tank. Plus the frag tank return bubbles into a refugium in the garage before returning inside. It's the inside of the home is what's the issue. The fresh air in the garage is the same issue with kalk. The problem is in the home, I can bring in all the fresh air I want but inside the house just adds all the co2 right back in. The only time I get a ph rise is when I open the windows in my home, which isn't often as I'm in hot sunny Florida.
Dennis, I mean have you seen any negatives from the low ph, such as thinned sps tissue? Slow growth can just be assumed as most people think they have slow growth but when you posted your full tank shot I wasn't impressed with your growth, especially on the newish reboot of your system.
I'm sure you know Brad,(reefnjunkie) and his corals are some of the largest I've seen. I reached out to him also about low ph and he told me not to worry about it at all as his tank runs from 7.65 to 7.95 on the daily swing. He said he tried everything possible to raise ph and never noticed a difference on growth. The only difference he said he noticed was on his wallet.