Heating possibilities:

Poly pro Tanks

pump outside, heater inside

pump outside and heat exchanger outside

pump outside and grid coils inside

pump inside and filter outside

pump inside, filter bag and agitation system

With stainless steel shell and tube heat exchanger

Stainless steel tanks

pump outside and tube heat exchanger

outer tank of stainless steel “double boiler” tank with gas heating

Double boiler tank

electric heating outside