PH is *always* a CO2 issue. Remember PH is a mathematical output of Alk and Co2 - so unless your alk is crazy low, the issue is with CO2 (could be co2 produced inside the tank or in the air outside the tank).
For those of you not seeing much impact from a CO2 scrubber, do you have a lot of surface agitation elsewhere in the tank? This surface agitation could be working hard to equalize with the CO2 in the air and be "outcompeting" the more oxygen rich air your skimmer is working to add back in. It's for this reason that CO2 scrubbers seem really inefficient and unappealing to me.
Like
@Turkeysammich already said - the best thing you can do is open a window.