One and a half or two inch is usual.
As pertaining to what? Sizing the heater to the pool? Length of run time to heat the pool? Proper gas line run and size of pipe to use? What brand to use? How to hook the heater into the system? Natural gas or Propane? And quite a few more k
Not sure what you're asking. Do you need to know size of piping or what kind of pipe to use?
PVC pipe is fine
This depends on the temperature and the fluid.
Minimum 3/4" pipe.
This depends on the size of the pool. Generally, when you buy chlorine, it should say on the bag or box how much to use for what size pool.
yes but depends on how much you put in the pool and the size the pool is
no
That all depends on what kind of pipe, the size of the pipe, the size of the insulation and the purpose of the insulation. If insulation is important: You will want to use a clip that won't crush the insulation. (On an air conditioning line, for instance, because it will sweat and could cause water damage. Or a pipe that could freeze) FYI: Insulation should not be crushed and don't leave big spaces between pieces. If this clip will be holding any amount of weight: Than I suggest attaching the clip to the pipe and insulating around the clip. If it is something like a heating pipe in the basement than insulation is more of a luxury than necessity It shouldn't really matter too much. But the better you insulate the more efficient your heating system will be. Good luck!
I never use any pipe under 11/2"
Flex pipe should not have been used in your pool construction underground. It may be against code in most cities. The use of rigid shcedule 40 or sch 80 PVC is standard.
You need to determine the: gas heater size for the specific pool/spa (with spa use no less than 400,000 BTU). ( how fast do you want the spa to heat to temp?) length of the gas run from the gas meter to the heater pad. size of the gas meter size of the gas pipe at a minimum. Ken