You can also bypass some of the water past the heater and thus the heater has a better chance of heating up what water does go thru the heater. When you start the heater up and you hear the sizzling of the water dripping, open the manual bypass, if you have one built into the pool plumbing of the heater, and the condensation stops. So if you have this issue and no manual bypass built intot he pool plumbing of the heater, add it and see how it then acts.
Your mileage may vary......LOL