When this thread first started, I had very little recent* experience to draw on, in order to offer opinions and advice - other that just how easy it is to (very, very nearly) fall in one.**
Since then, I have got roped into a closer relationship with a pool and would offer various insights now.
Be prepared to be continuously "sorting something out". Every time you 'sort one out', another will reveal itself.
An example - The circulation system had multiple air leaks which made it difficult for the (automated) pump to start reliably. These leaks were systematically (?) remedied, but eventually, the real source of the majority of the problem (probably) was revealed to be the seals at each end of the heat exchanger for the water heating system. When the pool 'went dormant' for the winter the opportunity was taken to open it up and sort the seals out. I had hoped that they might just be cleaned up and replaced in a better manner - one of the couplings was clearly cross-threaded and the other was difficult to tighten fully, due to access issues. Opening it up revealed that the cross-threaded seal was a bit knackered as a result and the seal at the other end just wasn't there at all - it had been 'replaced' by a handful of Boss White and some hope, which had faded a bit...
"Never mind", I thought, "let's just get some new seals and it should be OK" The fittings seemed alright, even the cross-threaded one went back together with no problem, when straightened up.
Many pool suppliers have claimed to have the seals, but when challenged to actually supply them, none did. The manufacturers, in Germany, were just proper weird. The bloke there was very unwilling to supply any spares and recommended that I replaced the fittings - they are perfectly OK and are glued on - replacing them would probably make things worse - all it needs is new seals. He suggested that I contact their UK agent for the seals - they weren't the slightest bit interested. Some other places that I tried still have the seals on offer on their websites, weeks after they have admitted to me that they don't have any or any intention of ever supplying them.
I have one place now offering me the seals at a ludicrous price.
The seals are "specials", not used anywhere else - I initially expected to maybe even get them from Plumbits or GPT on Marston Road, but no.
They are essentially a flat gasket, but with a semi-circular rib running round one face, to locate in a groove in the fitting and stop the seal from being sucked inwards when the pump isn't running - there being about 3psi of 'negative' pressure in those circumstances. I suspect that a plain flat gasket would be OK, but the 'real' seal would be better, I suppose.
Anyway, measuring the groove in the fitting has revealed that it seems to be very close to a standard o-ring groove so I have ordered a couple of o-rings and we'll see what happens. This will also allow the fittings to have an extra turn of thread engaged, which won't go amiss.
In general, I would say - be prepared to deal with people who don't really know any more than you do, but do know that there's money to be had..
*I was last in a swimming pool in 1967, in a canoe.
**There are moves in Ireland to make it compulsory for this government minister to perform all future swimming pool opening ceremonies.
Within thirty minutes of him falling in, some wag had put warning tape around the ornamental pool in front of the government buildings in Dublin.
