You have been provided with good advice. I will say this. Occational day time temps of 79° is just fine. This is usually the average ambient air temp. The warm side of the tank will more than likely be correct

Lower appetite isn't uncommon for a frog of 1 year of age and especially so for males. When they begin to call they will lose their appetite some, so once he is no longer stressed and it his appetite only increases slightly it will be due to your frog having reached maturity. He is a beautiful albino cranwelli.

Follow advice given. As long as he does not lose weight and does eat at least some food and a decent amount between each time he eats he should be ok. Keep a close eye on him.

Carlos is correct about trusting water companies. Some actually use bacteria to protect pipes from corrosion.