Hey Michelle, I would disagree that 'main drains are a waste', they offer an alternate suction source (very useful if the water level is too low for the skimmers to work) and gets the water from the bottom of the pool to the filter system, you can also just brush debris into them as opposed to setting up the vacuum. Having said that, they may well be more trouble than they're worth (without scuba gear, they can't be winterized properly, so that line tends to fail and repairing it is an expensive undertaking, which may need to be done every few years. Installing a line that has a good chance of failing doesn't make much sense, so the company I work for doesn't install them. What we do is install 2 'low suctions' in the deep end (they're regular return fittings located 28" down on the pannel) to provide alternate suction and get some of the lower water back to the filter.
On a 20 x40, we put the skimmers on one side of the pool (evenly spaced). That same side has 3 returns, 1 by each corner and one in the middle of the skimmers. On the other side we put 2 returns directly across from the skimmers (this works well for us, everything finds it's way to the skimmers - including toys, check your skimmers regularly to insure that the weirs don't get stuck closed as this could cause pump cavitation).
One other thing we do that you might want to think about is the addition of 'low returns' (28" down again) to distribute heated and chemically treated water down in the water (heating the top of the water is kind of a waste, 'cause heat rises) This may cost you a little extra in plumbing (more pipe and an extra valve) but it's a sound idea. If you decide to go with what I've suggested, make sure your installer sizes the pump and filter apropriately for the extra lines. Best of luck with your project and welcome to the forum! - Waste
Bookmarks