My suggestion is to temper a couple of gallons of water. Keep two or more one gallon jugs of tap water in the fridge, and then bring it up to temp as needed. It is easy to mix some warmer water to obtain temp needed. Some folks think that only developer temp is critical, that's true to a point, but keeping all chems at or near(+-1 deg)is important to avoid reticulation of the emulsion. Some films are more sensitive to temp changes than others, so I err on the safe side and temper all my liquids the same.