Pool heaters today are protected against corrosion to a certain degree. Cupro-nickel heat exchangers for example can withstand excessive salt and chlorine.
Now if your pool has a chlorine leak and you do nothing about it, or if you disapper for a few months and a chlorine outbreak goes unnoticed, you can certain destroy the heat exchanger, copper nickel or not.
Even with tougher components you still need to keep acidity and salinity levels in check. You need to monitor PH, chlorine and calcium hardness levels on a regular basis. Unless you like to update your heater on a regular basis.
If you are installing a salt cell you must use a corrosion resistant check valve to prevent highly concentrated chlorine levels entering the pool heater which will result in serious damage. Salt cells and chlorinators must be installed after the pool heater to prevent accidental chlorine leaks and backsiphoning.
Calcium and chlorine can build up around the sensitive parts inside your heater and corrode them over time. There is a device that has be used in the marine industry for years namely the zinc anode. It counteracts galvanic corrosion and helps keep metal components from being damaged by saltwater.
It will protect anything metal inside your pool including steps, water features and vents.
Most heater damage is caused by improper PH levels, chlorine leaks are easy to spot and not many people are daft enough to add a salt cell or chlorinator before the pool heater, in the equipment chain. Unchecked PH levels can become a silent problem and this will over time wreak havoc with your equipment.
If your PH levels have went unchecked for a while and they are out of balance you need to backwash your pump, filter and heater to remove and build up of acid or calcium inside their components. Acidic water can remain trapped and cling to heating tubes and metallic elements, which will slowly eat away them like a silent parasite.
You will notice it one day when something refuses to work. Then it’s abandon pool and wait for spare parts and a technician, or just abandon the pool altogether as the repair bill is too high.
For electric heat pumps, a titanium heat exchanger is the equivalent of cupro-nikel. It is built to withstand salt water corrosive to a certain level. Remember though that regular PH checking (daily if you aren’t sure) is the best way to maintain your expensive pool equipment. And don’t be afraid to SHOCK when you need to!