My adorable and awesome better half has decided she wants an indoor pool :lol: its not that big 8x18, 4' deep, this will be a new addition to the house, my idea is excavate, concrete block wall on compacted clean gravel, 3'' of plastispan closed cell rigid foam, attached to this flexible pex tubing for solar heater/propane boiler, pexline buried in stucco and then fiberglass roving and gel coat (wow sounds easy!) as I cannot find anything on the net about this Im just hoping for someone to show me the error of my ways or some advise to better the end result, thank you in advance for any help and if feasible I will do a complete build pictorial. Steve