Pool Pilot piping and Heater

I have my PoolPilot soft touch on order and am planning the piping changes needed. I have heard that the cell should be the last thing in the system before the water returns to the pool, but I wonder about the heater. What is the correct configuration.. cell before or after the heater?

This is a 20K gallon IG pool, no spa, with pump, sand filter and natural gas heater.

Putting the cell before the heater potentially increases the corrosion rate of the heater due to Cl content of the water, while putting the cell after the heater exposes the cell to hot water when the heater is in use, which might be bad for it and certainly messes up the temperature compensation.

Allow about 4' of pipe before the manifold. This will allow some cooldown of the water before it hits the tri-sensor. Yes, the automatic temperture compensation feature will increase the output based on the heater temperature increase. However, this may be about 7 - 10 degrees increase and shouldn't affect the Soft Touch's output much.