Quote Originally Posted by gordonhyde View Post
I don't see how using this info can help me in pre build planning.

Mark:
Is the 50feet an average number? How can you tell that is close?
First, the quote above was for existing pools so you cannot use that to determine head if your pool has not been built.

The pool plaza link was to familiarize you with head loss and method of determining the optimum pump size. At the bottom of the pool plaze page is a link to calculate head:

http://www.poolplaza.com/pump-head.shtml

Again, those are only approximations but they may get you closer. The proper way is very involved and requires some knowledge of hydraulics engineering so I generally don't recommend that.

Most swimming pools will have a head loss of between 45 and 65 feet of head based on experience so given your 2" plumbing it is likely that you will be well below 65 feet of head if you choose a low HP pump. Head loss depends on a lot of things, pipe diameter, number of bends, equipment, pump size and few other things. So for a given set of plumbing, a higher HP pump will see higher head loss than a lower HP pump.

A 1 HP Northstar will supply 80 GPM for an 8 hr turnover with 60 feet of head so that is a safe bet. You will likely have less than 60 ft so your flow will be higher which is OK.

To compare, I have a 1 HP Northstar 2 1/2" suction pipe, 2 skimmers, 2 mains, 2" return pipe, 4 returns and about 50 feet to the pool. My head loss is about 55 ft with a flow of 90 GPM. So you can use that as another data point.

With 2" on the suction side as well, I did a quick calculation and my head loss would bump up to 60 feet with a flow of 86 GPM which would still be ok for you.

So I would recommend not going above a 1 HP pump unless you plan on using the same pump for a Spa or additional water features. Also, I run my vacuum on the 1 HP so I don't think that would be a problem.