So I've got a 13.5 evo that is suffering from low PH. I've done all the usual. I have some chaeto in the back running lights 24/7 and it is growing like a weed. I am not running a skimmer. I just installed a air exchange unit pumping in fresh air which is right beside the tank. I can't hit 8.0 during peak and dips to mid 7.5's at night. I've confirmed this number by using 2 different test kits, other than the main hydros system monitoring it. I also don't have enough demand or evaporation for kalk to make much of a difference, (or will it)? From what I see, I dont think there is much else I can do?

