I am building a 25k gal pool in the philippines, as there is no qualified pool builders in that area. For this 25k gal pool, it seems that 2 skimmers are adequate. I have heard differing opinions on the amount of returns to install. Some Pool experts have said that 2 each 1 1/2" pipe size returns are enough. Others say that 6 or 8 returns are better to create a smoother flow thru the Sand Filter. My current plan is to purchase 2 of these builder kits WaterWay Renegade Vinyl Liner Skimmer - Builder's Pack - PoolSupplies.com which would have a total of 6 each, 1" returns, which 3 each of these returns will be plumbed in to two 1 1/2" separate lines (did that make sense?), meaning 2 each 1 1/2" lines going out to 6 returns spliced in to 1 1/2" piping. Of course the less penetrations thru the pool wall means the less chances for leakage and piping issues later. Also planned on putting one of the extra main drain connections stubbed thru the wall and capped for now for future water slide installation. Plan on using a 1 HP circ pump. Comments are welcome !