Sounds like you are making progress!
Don't worry about pH 7.85 that is good enough! pH varies a lot, for the health of your animals, the other parameters seem to be more impartant, at least as far as I read on here. Maybe you will not have the fastest grwoing SPS at that level, but there are beautiful tanks just using softies...
It will be interesting to see what happens now that you will have more air circulation. Maybe the pH can raise even further. In any case, I would strongly recommend not to add any pH buffer where you do not know what is in the mix. Buffers are a strange animal and you don't want to add something that might keep your pH in check but messes with any of your other important values.
The fan for your stand is an interesting idea to further improve air condition around the skimmer intake. Could work but you run the possibility that you will have more evaporation from your sump! Can't you get an adapter for your skimmer or a bigger hose? that would allow you to move the skimmer intake outside which definetly would improve your situation as it seems from your experiment with your fans!