Debating the turnover is a myth belief

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
12,872
Pleasanton, CA
Pedantically the wide spread advice all over the internet is that you require 1-2 turnovers is a general easy to understand concept that is not really that far from a practical generalization that could be applied to 80% of pools to provide good filtration support.
I don't believe it is anywhere close to 80%. The key word here is "require". Again, sanitation is required, filtration is not. What is required is enough run time to distribute chlorine throughout the pool. For manual dosing, that is only about 30 minutes for the average pool. For SWG pools with properly sized cells, that might be 2-4 hours. Plus with low speed of a two speed pump or a VS pump running on lower speeds, it will be a fraction of a turnover. In the winter, I average about 0.25 turnover per day and in the summer with solar running, about 0.5 turnover per day.

If you turnover your pool water once, then industry studies have shown 64% of your pool water will have gone through your filter. This will generally remove suspended particles from your water.
64% is a number based upon full mixing of the incoming water with the existing water. But in reality most pool owners point their returns to create surface patterns to help with skimming. This results in much more water returning back to the skimmer directly from the return which will result in a far lower filtration rates.

But again, any particles that remain suspended in water cannot be filtered out a standard pool filter. In order for particles to remain suspended in water, they need to be less than 2 microns. Everything else will sink to the bottom of the pool before it can be filtered out. So you are better off using a floor cleaner than longer run times.
 

JamesW

TFP Expert
Mar 2, 2011
16,978
The concept of “Turnover” started with commercial pools, which do have turnover requirements.

To some degree, the concept got transferred to residential pools.

To a large degree, pool builders were just trying to give homeowners a simple rule of thumb to make sure that they got enough filtration.

Most builders originally installed oversized pumps and told homeowners to get at least one turnover.

This was very simple, but costly advice. Since builders didn’t have to pay for the electricity, they didn’t much care that there was a 1.5 hp pump running 12, or more, hours a day.

Builders didn’t really have much incentive to figure out how much filtration was actually needed. So, they erred on the side of caution and just made up a figure.

The guideline of 1 to 2 turnovers per day can be considered to be a “myth”, in my opinion.

Some people like continuous skimming and filtration to keep the surface clean and the water extra polished. With a variable speed pump, this can be done relatively inexpensively by running continuously at low speed.

In any case, every pool is different and each person should do what works best for them based on their specific situation.
 

JJ_Tex

Bronze Supporter
Jul 17, 2019
597
Prosper, TX (DFW)
I was thinking about this thread last night when we were cleaning up the kitchen from dinner. We had chicken, so we sanitized the sink and dish that contained the raw chicken to kill any nasties left behind. After that we wiped down the counters and swept the floor.

Those are two different actions we used to clean our kitchen. While both are required, the immediate concern was to sanitize the sink since that action greatly reduces the risk of food poisoning. Sweeping up some crumbs off the floor was secondary and important to keep the kitchen clean, but no amount of sweeping would do anything about the potential salmonella in the sink.

The same goes here for pool maintenance. To properly maintain your pool, you need to sanitize your pool and clean the water. Chlorine sanitizes and skimming/cleaning/brushing/filtering cleans debris out of the water. Both are required, but the priority should be sanitizing first to keep your water safe and algae free.
 
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Leebo

Admin
TFP Expert
LifeTime Supporter
Jul 21, 2011
9,137
Eastern Ohio
The actual pump run time you need primarily depends on the relative size of your pool, the pump flow rate, the amount of debris that falls into the pool and the use of solar panels (or not). Every pool is different and each pool owner needs to figure it out for themselves. Historically, the rule of thumb has been to run the pump at least 1 turnover per day. However, that has turned out to be a very poor indicator of actual required pump run time.
That’s the exact quote from Pool School, opening paragraph. I’m not sure there’s anybody in this thread who’s saying filtration isn’t needed. Same time, that’s not the “turnover myth.” The term “turnover” was an over generalization that said you MUST run the pump enough to filter all the water once a day. That’s false. Some need more. Some need less.