Stub the returns through the shell with 1.5" and feed the stubs with a 2". Keep the 2" outside the shell by a foot or so. Please, don't use flex pvc, even if it's free. When it fails, free won't be free anymore.

Scott

Thanks Scott. No flex pvc. I do understand those issues. So the eyes in the pool that return the water connect to a 1.5" pipe? For some reason I assumed 1". I hadn't really discussed it with my plumber yet.

jvmjr,
You will be able to buy directional eyeballs that install in the 1.5" pvc stubbed into the pool. The eyeball fitting comes with several sizes of openings that can be adjusted.
Good luck.

If you don't trust your builder's plumbing design intelligence, then I would recommend the 2" pipe feeding the 1.5" stubs to be in a loop all the way around the pool. Each stub comes off in a T-fitting from the loop. That is the easiest way for all return lines to have equal pressure.

It wouldn't be unheard of for a pool that size, and with the water features enabled, to benefit from the use of 2.5" or 3" pipe from the pad to the pool loop/drain lines. Of course that also depends on the distance from pad to pool as well. I lack the skills to do the math, but from a long-term cost benefit aspect I bet 2.5" pipe runs would pay off in reduced operating costs with the VS pump. Example: I use a Pentair VS-3050 pump and 2" pipe on a 16K gallon pool with about 20 feet from pad to pool. I can run my pump (with no water features) for about $7.30 a month. Electric costs are not linear with flow rate. I tested for electric use at double my pool flow rate (somewhat closer to the size of your pool) and I ran $46 per month charge. Assuming Pentair equipment with automation (like Easytouch) you will be able to see the numbers and do the calculations yourself - unfortunately not until after install.

Our builder use 4" for the suction and 2.5" for return for everything, main pump with solar, jet pump for spa, and waterfall. All pumps are 2hp jandy stealh. The 2hp pump for the the waterfall is total over kill, but if the main one failed, i could switch is out with waterfall pump that was my thinking at the time. Buy variable speed pump. Our pool is 16k gallon.