Healthy fermentation there. I usually wait to change the water until fermentation slows down some and won't immediately gunk the water back up.
Also, a cup of water should work pretty much as well for your temp probe (less space/carboy used).
Edit: I always use starsan for my blowoff (takes like 20 seconds to dump a little in a gallon jug and fill halfway up with water). Others on the forum just use water so it's up to you--im a bit obsessive with sanitation