So I took the entire tank apart to start the process of lining it.
During this time I'm double checking the plumbing system -
this is a full rookie design.
The pipe on the right will take water out of the tank to the cleaning system.
The pipe on the left is the return for cleaned water coming back into the tank.
I've lined the entire area with foil insulation and placed the water bed heater.
Here's a view from the back of the tank - you can see the controls.