I am guessing you are referring to a perimeter overflow ? Give some more specifics on the design.

There is a slit all the way around to make it the water the same height of the coping

There are several different ways to build a perimeter overflow.. I would suggest that you look at some projects your contractor has completed in the past. The design goes much further than just the shape. Where does the displaced water go ? How much foreign debris will the pool encounter and what measures will be taken to handle it? Look in this forum for "Need help negative Edge pool" thread. The builder did not make the wall level and now the client is not satisfied with the results.

This would be the pb's first one, so maybe I should shy away from the idea, thanks for the help

I would NEVER be the first perimeter overflow client of any builder. POF pools need to be so well planned, and perfectly executed to achieve desired results and meet and exceed all expectations.

I once stayed at a 5star hotel that had a 3 level POF pool. It was gorgeous, but all night I could hear improper draining of the overflow water, gargling and getting air locked. There is a TON to doing it right.

I do not have a knife edge, but I do have a 12 foot infinity edge. If I were to do it again, I would install a skimmer in the catch basin. I have my automation set so that the infinity edge pump comes on in the middle of the night so that it skims off any debris. Even w/o doing this and only having it operate when we are swimming, the catch basin catches a lot of debris with nowhere to go.

HERE is a great article on the pro's and con's on a knife edge pool (and also other styles)

ncrealestateguy....you should not put a skimmer in the catch basin due to displacement of the water. The skimmer will be either completely flooded or sucking air. In either case it is not functioning properly. In fact, the catch basin is your skimmer and I have seen qualified professionals build edges without a single skimmer in the pool for this reason. If the client plans to use the edge a lot then a skimmer is next to useless because of the draw and edge creates and the debris will end up in the basin anyway.

knife edge is a great design in the right yard. $9k however would not even cover material costs to do it versus any form of traditional pool - and you say that you would be the first from this PB? YOu would have to be crazy to be the first knife edge pool he builds.

Based on the feedback we went against it... Thanks for the help

Ludwig, I think you posted the wrong link. That just tells what the three basic bases of the pool are, nothing about the fancy stuff.

The main reason that made me stop my contractor from making a knife edge pool (which he was going to build for me by default, without telling me and without extra charge) is that a glass of champagne would not sit properly on a slanted pool edge! I don't see any advantages to an edge like this. Besides, if you want to lie down, walk around the pool, or just hop out without using the stairs, it would not be comfortable or safe for that matter.