Do you guys use flexible pool pipe as we seem to use lots in the UK.
Have found it does have a few challenges when testing, If too much pressure is used it expands the pipe and gives misleading test results as the pipe tries to revert back to usual size.
Have also had a leak that took a lot of thinking about to resolve;
Pool leaked with flex pipe and showed air on suction line, isolate to one pipe and pressure test, not a thing.
Run system and air appears, did all the usual re make of joints, checked valves etc. Still air but no leak under pressure. The pipe had been sliced sideways so when pressure was applied it closed the leak, under suction the flap of pipe opened allowing air in. For sure leak locating can be frustrating at times but rewarding eventually.

I see lots of spa flex being used for new pool installations. We ripped up three different locations of a 1 year old pool deck to find defective spa flex. Called the company and we were told that they do not call this product pipe. They refer to it as hose and that it is not rated for underground use, which voids its (very limited) warranty.
Ants and termites also seem to like it too.

The stuff we use is grey or blue with a wall thickness of 5-6 mm and a helical wound reinforcing. Not to be confused with MDPE or vac hose that some use! I guess we don't have the termite problem either.
Because it flexes it doesn't get distorted with the backfill material.

Flex should never be used on suction lines as it tends to collapse at the glue joints.

Flex pipe is used extensively in eastern Canada. We don't have a termite problem here. Have not had any problems using it for suction. However the glue joints will not withstand the pressure from Polaris type cleaners and a leak is guaranteed if used for that purpose. Some builders have clamped the pipe instead of gluing and that has caused problems under pressure

Always better safe than sorry regarding suction and flex I believe!! I work in the Los Angeles California area, including Beverly Hills and other high end markets and flex has been great in a lot of applications, but I have seen too many suction line leaks when plumbed with it. Happy hunting!

Have had three pools with flex pipe used on suction side with apparent leak showing air in pump pot. Home owner stated pool was not losing water. all three pools pressure tested fine. Leaving chlorine tablets in the skimmer without pool running had concentrated chlorine and swollen inside of spa tubing to equivalent of one inch diameter.Pump was starving.After digging up lines each had approximately 3-4 foot of swollen flex pipe.

We use mechanical joints on the flex, glue doesn't last especially when the pool gets overheated!

i find a lot of leaks where flex goes into fittings and as flex tends to curl you get one side to the pipe pulling away from the fitting give it 2 months and im out there replacing flex with pressure pipe, in Australia im also finding plumbers are using it because they are lazy and dont want to trench properly, i dont like using it but when used outside of the shell i use like a foot of flex glued into the flared end of a pipe and i use this to get around those odd corners and i havent had any problems with that