Ethan, this sound like good humidity to me, though in many cases you want lower humidity in the fridge/cave. 50 degrees though may be too cold for some cheeses. If you want to reduce humidity, use a tray of kosher salt in the fridge to help absorb some of it and clean up excess water. If you want to increase humidity (say you are making a Brie), age the cheese in a closed or partially open container that is inside the fridge. This method also would not affect other cheeses in the fridge that need the lower humidity. It will also prevent cross contamination as the more humid cheese tend to grow more mold and bacteria that often doesn't belong in your Cheddar, Tomme or Jack...
I also suggest that you get several battery operated hygrometers/thermometer combos. Leave one outside when you drain and dry the cheese, another one in the fridge, another one in your aging box if you use one. You can buy those on eBay for a few bucks. (see:
http://shop.ebay.com/?_from=R40&_trksid=p3907.m38.l1311&_nkw=digital+hygrometer&_sacat=See-All-Categories )
I am new to pH meters, but also new to harder cheeses. So far it seems that past failures to make cheese were not related to wrong pH readings, but as I get more serious, I want to do this properly and also develop techniques that would yield consistently good results, so I guess that just as a serious baker switches to quantities by weight rather than volume, a good cheesemaker will time processes and control quality with a pH meter. That being said, I am just learning to use it now. I also think that if I would have tried using it when I began making cheese it would be just too many things to remember and do at once and it would have confused me and made me mess up my cheese, so I am happy I started without it, but now I need it.
Here is a photo of what this looks like in an aging box which I cover and place inside a wine refrigerator