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does neg. edge pool require two pumps?

Posted by shellip (My Page) on
Sat, Aug 20, 11 at 8:23

Still working on the rebuild of our neg. edge pool. PB had called in another crew to do the rebuild. They said there need to be two pumps, one for the gutter pool and one for the reg. pool. PB said only need one pump. Have read all your advice on one vs. two filtration systems, but what about one vs. two pumps? Main Pool is 16x36 and from 3-6' deep and gutter pool is 3x36 and 3' deep. Plumbing lines are 2" and are about 70' from the pumps at the far end.
thank you for your continued support!
arch. plans

Follow-Up Postings:

RE: does neg. edge pool require two pumps?

It works better with two, one for the main pool and one for the edge.

How long will your edge be?

Are you looking for it to be a sheer off the wall or for the spillage to hug the wall?


RE: does neg. edge pool require two pumps?

Looking for the water to just spill over the wall. Do not need a "gushing waterfall". New crew foreman said a single 2HP variable speed pump will do the job, but he always has used two pumps. PB (who has hired new foreman)insists one pump is fine. PB is giving us a rough time on just about everything at this point. May have to add the other pump on my own, and just get his guys to plumb for it. What size do you suggest for the gutter? It is 3' wide x 3' deep by 36'long.
Thanks for your input.

RE: does neg. edge pool require two pumps?

The flow for the wall will vary with bather load. Having a variable speed will allow you to run more efficiently regardless.

If you do put a second pump in, I suggest adding a filter too. Catch basins catch a lot of the debris from the pool. With a dual pump system, without the 2nd filter, it will just get shot back into the pool.

Please remember, there are builders here that have built these pools and that I am not a builder. I just fix and augment existing pools. Some will disagree with me and say one system is enough. What your needs are may differ from what I consider ideal.

What is the PB's line of reasoning for a single pump system?


RE: does neg. edge pool require two pumps?

Scott is correct. There are several ways to plumb these pools. I have usually used a single pump system. As Scott indicated, it depends on the look you want on the backside of the dam wall and the length of the wall.
I treat the basin as a big skimmer and pump everything thru the filter. A well built wall will only require 1-3 gpm/ft of wall to look good. Variable speed pumps work very well for these pool applications.
It's also a good idea to run the pump while the pool is being used so the kids don't splash out so much water that the basin is overflowing.
2 pump system: One pump filters the pool water just like a normal pool. The second pump draws unfiltered water from the basin and puts it in the pool. The second pump should be running while the pool is in use(splash out reason I described above). It will also need to be run each day because the automatic water fill is placed in the basin.
IMO the one pump system filters all the water all the time and I find it more efficient.
Having a hand held or other electronic control is really handy for this application when you want to turn the pump on without having to go out to the equipment area each time.
Biggest factor to good operation is sizing the basin correctly. Better to big than too small. You might ask your PB how he calculated the basin size. He should be able to tell you how much water will be in the basin with the pump running and about how much freeboard area they are allowing for. Good luck.

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