Would there be any harm done if you took a rena smartheater and used a reducer and hooked it up to the fx5 intake? the inlet on the heater for the intake tube is probably 1/2 inch or so
You would substantially reduce the flow of the fx5 well below 200 GPH. Possibly put the rena heater under to much negative pressure ruining it and you might increase the chances of getting micro bubbles.