I see this a lot, but I'm not sure it's true. For retangular pools for sure, as in that case the blocks are holding up the sides, and so have a lot of force transferred to the blocks, which is why we see so many cracked pavers on rectangular Intex pools. But for a vertical pool? My engineering mind is saying there shouldn't be a lot of force, but I could be wrong. We'll see shortly.Just my 2 cents but you've spent sooo much time researching, preparing, constructing, money and doing everything so well why such a rush on one of the last steps and not putting blocks under the legs? That pool could be there for a long time (about 5 years on mine so far). The weight on those legs is tremendous, I wouldn't go without concrete blocks.
I think it is definitely more critical on the rectangular pools. When I put up my little 15’ round pool I just used a standard brick under the legs. It was fine for a while, but after a year or a year and a half I had a couple where the leg was off center to start with and over time the brick started twisting and the side with the leg began sinking into the ground. The rectangular pools have a whole lot more force on their legs (There have been a number of people who have had 2” pavers crack under the rectangular pool legs), but there’s still a pretty good amount of weight under the round pool legs.Okay, so the legs sunk into the foam about 1/8-1/4" or so. I will put some wood blocks or pavers under them in the near future. I believe I can do that without draining the pool. In the meantime it is fine though.
Easier for sure, but it would take a day to drain, get the blocks in, and another day to refill and my wife would NOT be happy (see comment on eaiting 4 years for a pool above).Unfortunately I don’t think you’ll have any hope of getting anything under those legs without draining the pool. I’ve seen some people try to jack up the legs to reposition them or put something under them, and you might be able to get away with that for one or two legs, but I think trying to do that for every single one of your legs is going to be way more time and effort than just draining the pool. Not to mention that there is a lot of question about exactly how much stress the jack puts on the frame of the pool. It might be worth the risk if you just had one leg that you had to fix, but not for all the legs.