I am reading the manual for the heater my PB is going to install. Its the Pentair MasterTemp 400.

On page 3 of the manual it states:

"NOTICE: Do not use this heater as a heating boiler,
water heater, or for heating salt-water pools. This heater
is intended for use in heating fresh water swimming
pools or spas only"

Do you have to use certain heaters if you want to use a swcg?