The following article addresses a challenge we often face in this industry.  A challenge with a solution..., and the solution will open doors to more business and success for all. 


First, I hesitated to write this as I know there will be some, who don't know me and will think I "being negative" or "uncaring", but that is not so.  It is because I care deeply about both the industry and all of us who represent it that I created the Pool Genius Network, that I serve this industry each day in varying capacities, and now, write this post.

As you read it, try not "judge" whether what I say is "true or false" but rather, "does it contain something that can help me or others grow, prosper, or improve".  (As much as is possible, that's how I try to frame everything)


The Analogy:


Of all the beautiful water feature and pool design elements few are quite as dramatic and breathtaking as a well designed "vanishing edge".


Also called, "infinity" edge, and "negative" edge, these pools have the distinguishing feature of a section of the pools perimeter serving as an overflow permitting the waters edge to seemingly "vanish" into the distance.


These pools are special, and the engineering requirements are not obvious thus making them the most problematic designs a builder can undertake.  That said, the absence of the "obvious" can also be a call to "learn more", and once these skills are mastered, the creation of trouble free "infinity" edge pools is flawless.

There are three catagories of "special" information that needs to be mastered:

  1. The "design" elements - the specific attention to detail required in the physical design of the pool and structure
  2. The "hydraulic" elements - the engineering of water supply, capture, delivery, transition, containment, and surge
  3. The "communication / documentation" elements - the clear disclosure of the operational differences of these pools including increased maintenance, water consumption, energy requirements, and part repair and replacement


The biggest problem with building a pool of this type however is "personal" rather than "technical" in nature.


You see if you "know" how to build it correctly, there is no problem at all. And if you don't know how to build it, the problem is easily addressed through research, education, and having a competent mentor available to discuss challenges until a complete understanding is reached. But the biggest problems arise not from "knowing", or even "not knowing", but from "not knowing that you don't know".


This last part of the equation, "not knowing that you don't know", is where the pursuit of the "obvious" results in "unintended" and often "huge" problems.


This not only occurs with contractors who build the original structure, but often is further exacerbated by the repair tech who applies further ignorance to solve the problem resulting in new problems, finger pointing, and a bad reputation to our entire industry.


I write this as I spent years developing the "craft" of constructing beautiful and technically difficult pools, and indeed made more than a few mistakes along the way, many of which were due to the total absence of training back if the early days of development of these now common features.  I also write because I was recently asked to look at a job that was not functioning as it should and found two of the most common problems with these designs, 1) the pump elevation was 5 feet above the catch basin operational water level  2) the catch basin volume did not account for "bather surge"... at all.


The builder was blaming the pump manufacturer for a "faulty" design as the pump was cavitating badly and was nearly impossible to prime, and was looking for a non-existant way out for the catch basin design flaw. But underlying it all was the real problem, they thought they knew, but were wrong.  It was the failure to understand or acknowledge that they "didn't know they didn't know".


You see, this characteristic transcends the challenges of "vanishing edge" design and carries itself to the furthest reaches of our experience..., if we let it.


Take a moment to examine your thought process.  This trait can be hidden by a certain "pride" we as men often have, but if given focused attention it can be recognized. Once recognized, commit to open your heart and mind to learn new things.  Become a "student" of life and of this wonderful industry which provides beauty, health, fitness, and happiness to so many.


And if I can every be of help to any of you, just ask!


May you all have the best year ever..., learning new and wonderful things as you traverse the challenges of each day.



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  • I am looking for a simple trickle affect nothing spectacular.  The trough is longer than 8 x 10.  I have more than enough figured for capacity.  Also I will have the water away from the structure and I have piles done because I'm close to the water.  Here are some pictures of my work.3423780926?profile=original

  • Hi Brandon,  a few things missing here... the length of the wier?  height of the transit? length of the trough? (assumed is 3' trough depth by 2' width, missing dimension is length.)

    If it is "assumed" that the weir it 8' long and only a trickle is needed, and also assumed a very level weir with a smooth surface then less than 50 GPM is required to make the overflow work and the 3/4 HP is fine.

    Also assumed is the 3/4 HP overflow pump is drawing from the trough and the jet pump is drawing from the spa itself. (sump locations are not defined)

    Also assumed is the autofill is located in the trough, not the spa and set to refill to "operational non-surge" water levels.

    And... that the surge capacity of the bathers has been calculated at the largest spa capacity to prevent trough overflow (I use 35 gals. per bather and this spa could have up to 12 people??)

    Be sure to incorporate an overflow in the trough that directs water away from structures to handle rain overflow.

    Best to you on this project

  • Hi I am new to this site.  I am working on a 6 x 8 Gunite Spa with a sundeck before going into transit off a negative edge.  I have 2 sumps in the trough that will be pulled with a 3/4 H.P. pump and being filtered and heated back into the Spa through 2 bottom returns in 1 1/2".  I am only looking for the water to trickle down.  I am using a 3 HP pump through 2 sumps in the spa to be returned back to the spa  that will have 12 Jets in 2" plumbing.  Also a 2HP blower will be used with a hartford loop and 1' above water level.  I am using an auto fill by Jandy for the trough.  the Trough is about 2' x 3' high.  Will this be hydraulically sufficient to have the affect I am looking for.  Thanks in advance. Brandon

  • Thanks for this blog Rex, and thanks Clint and Kevin for the useful comments. It's always awkward trying to re-engineer an existing system without blaming the installer. I've met with the homeowner and pool remodeling contractor and have gone over changes I want made to the contractor's design based on my experience prior to work being commenced. The contactor said, "Sure, we can do that. There's more than one way to skin a cat!" I laughed because my dad always said that.

    I was helping another contractor with some design flaw that we were trying to correct and the customer wanted to vent about the installer. My friend said, "I don't like to criticize another man's work. He may have had a reason for doing it this way. I've found that we can do it this way and... (insert reason why you do it this way)" It relieves some of the homeowner's concern and shows that you are a nice guy.

  • Rex

    I think you are right when you stated: "The biggest problem with building a pool of this type however is "personal" rather than "technical" in nature.


    It is human nature to be somewhat prideful. I can do it better my way perhaps attitude. The thing is though, the professionals who have designed and built pools like this, have made their mistakes and then refined them to prevent mistakes in the future. These are the professionals we should be calling on.


    It's never too late to ask questions and learn more no matter how many years of experience behind you.

    I have nearly 30 years experience and I still asks questions and learn something every day!

    It's always work in progress.

  • It is always a sticky situation when I discover someone else's mistake. On the one hand, the customer has a problem that they need solved, so they are already looking for some kind of explanation. Sometimes that means that I have to tell the customer that the installer or a previous repairman made a mistake. Other times I can just say what needs to be done now and not place any blame. Since I work with so many other professionals in our industry, I try to avoid blame when ever possible while still being truthful. 

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