We heat totally with a wood stove. Our 55 gal. tank is about 10 feet from the stove, placed basically like your digram. Never have had any problem with the temperature in the tank. What I worry about more than the heat, is the ash problem when the stove in cleaned. I make sure there is no opening in which the ash dust can settle into the tank. Don't know if it would affect the ph or not, just my precaution.
Anna
Anna
