How long does the pump really need to run?

[mas985]

Basically you need to be able to filter all the water once a day.

A turn per day is a bit of an outdated rule of thumb. You might want to have a read of this study done in 1984: http://consensus.fsu.edu/FBC/Pool-Ef...on_systems.pdf

Even back then, they recognized that only 3-4 hours of run time was needed for the average pool independent of pool size. Unfortunately, the rest of the pool industry has been very slow to adopt this philosophy. I run my pump only 4 hours per day in the heat of the summer and 3 hours of that is on low speed. Total turnover is only 1/2 the volume but the pool is more than clean enough for me. I would go shorter but I need the run time for the SWG.

Anyway, on to the OP. With a VS pump, the most efficient speed in terms of gallons pumped/watt-hr consumed is around 1000 RPM. I would start with that for about 6 hours per day and see how things go. Also, if you find your skimmer is not collecting enough debris, then you might want to have a separate 1 hour run period at higher RPM (~2500 RPM) for the skimmer.

[Dr.DieselFS]

Thanks for all the replies guys.. since I posted last I have had the new startup orientation and to be honest I learned way more from my own research, than by those guys. a tech came out to do the orientation because their startup people were out for personal reasons. I ask a lot of technical questions because I really wanted to understand the bare bones basics of everything and then build my knowledge from there. the guy was very hesitant to give me a good answer, like they were trade secrets or something. I do really want to start the BBB method just educating myself a little before I start that. I bought a basic test kit from LESLIES for now. im going to buy the Taylor soon (thanks for the suggestion). everything is going good so far. water is crystal clear and freezing a** cold. My pump will flow anywhere from 15gpm at setting 1 to 101gpm at setting 4. If I leave the speed at 2 which is around 30gpm and 1100rpm it takes about 8 hrs to filter my pool. its 12k gallons. I run the quick clean cycle 2x a week and scrub the interior and tile 1x per week and that seems to keep the water perfect. oh, its a cartridge style filter not DE sorry. Thanks for all the replies again.

[mas985]

FYI - Most of the Leslie test kits are just rebranded Taylor kits.

[Dr.DieselFS]

Gotcha...thanks a lot. Free info is much appreciated thanks guys. If you have any questions regarding diesel trucks or trucks in general i have you covered

[CarlD]

FYI - Most of the Leslie test kits are just rebranded Taylor kits.

That's true. They even have a rebranded FAS-DPD K2006 test kit sold from their online web site. It's exactly the same as Taylor's, but in a Leslie's box. It's generally a little more expensive than the kits available from Ben's signature link, but it IS exactly the same.

[Anonymous [GDPR] European in the UK]

A turn per day is a bit of an outdated rule of thumb. You might want to have a read of this study done in 1984: http://consensus.fsu.edu/FBC/Pool-Ef...on_systems.pdf

Even back then, they recognized that only 3-4 hours of run time was needed for the average pool independent of pool size. Unfortunately, the rest of the pool industry has been very slow to adopt this philosophy. I run my pump only 4 hours per day in the heat of the summer and 3 hours of that is on low speed. Total turnover is only 1/2 the volume but the pool is more than clean enough for me. I would go shorter but I need the run time for the SWG.

Anyway, on to the OP. With a VS pump, the most efficient speed in terms of gallons pumped/watt-hr consumed is around 1000 RPM. I would start with that for about 6 hours per day and see how things go. Also, if you find your skimmer is not collecting enough debris, then you might want to have a separate 1 hour run period at higher RPM (~2500 RPM) for the skimmer.

Hi Mas985,
Can I clarify if you mean 1 turnover per day (= roughly 4 turnovers to filter 98% of the water) or you actually mean 1 turnover being roughly 12000 gallons in 4 hours being 1/2 the volume?

I have varied the the pump run time and now filter 24 hours, That is at a slow speed during out of hours but sufficient to make sure almost all debris, leaves etc are skimmed rather than sink and require manual removal. During swim times the pump runs faster to keep a 6 hour turnover rate of 100% of the pool volume. My pool water has always been good in clarity but is now excellent and when the occasional manual vac is required there is no dust cloud produced when vacuuming just the occasional leaf (there is always one)

[mas985]

I was referring to my situation where I am only turning over 1/2 the pool volume per day or 1/2 turnover per day (~10k gallons). For me, one turnover is 20k gallons pumped. For the OP one turnover is 11.5k gallons pumped.

But water clarity has little to do with pump run time. Clarity is more about chemistry. What makes a pool cloudy is usually algae and not debris. Most debris either floats and can be cleaned by the skimmer or sinks and can be cleaned by a sweep. Pump run time is basically for these two things and for the distribution of chlorine, which takes only about 30 min for a manual dose. So pump run time is more about aesthetics than anything else which is why it can be significantly limited to meet only the cleanliness needs of the pool owner.

[nefretrameses]

Interesting. I too was advised to run the pump basically for as long as the sun was on the water. That's about 9 hours in summer and 6 in winter. Since I read the article, I have been running my pump 2 1/2 hours and the water looks great. It will be interesting when it warms up to see what happens. Right now there is no bather load. (Water is 68 degrees)

Mark points out that longer run times may be needed for SWCG systems. I suppose the same is true for solar heat at times. During times when you want to get the most heat into your pool, you will want to run the pump for as long as you get a temperature differential (of some minimal amount).

[Anonymous [GDPR] European in the UK]

But water clarity has little to do with pump run time. Clarity is more about chemistry. What makes a pool cloudy is usually algae and not debris. Most debris either floats and can be cleaned by the skimmer or sinks and can be cleaned by a sweep. Pump run time is basically for these two things and for the distribution of chlorine, which takes only about 30 min for a manual dose. So pump run time is more about aesthetics than anything else which is why it can be significantly limited to meet only the cleanliness needs of the pool owner.

Now that is what I also believed early on, howerver although chemical balance is important and customers who have poor circulation I usually recommend running a higher chlorine level to try and improve the water quality/clarity. From my original experiments and from studying other people work I now believe that clarity is also very much about pump run time.
Leaves spend only a certain amount of time floating before becoming water logged and starting to sink. This means there is an optimum time to make sure they are removed by the skimmer/s. Like wise other dirt that ends up in suspension, colloids etc which are the cause of turbidity in water. If you push the water around for a few hours some is removed and after the pump is switched off, some sinks, as you say for manual removal. Manual removal however isn't that easy as small particles easily get stirred up and back into solution as most pool owners will admit. They start with a clear water but after manual cleaning the water loses that clear look for a while until the dirt settles again only to be stirred up by swimmers etc.


http://en.wikipedia.org/wiki/Turbidity

Running the pump for 24h constantly as we know from the water dilution principles means that 98% of the water has passed through the filter after 4 water cycles and that means far more dirt and small particles are removed and if the filtration is good enough colloids can also be removed. This greatly improves the water clarity and means chlorine can last longer and there is a lot less manual cleaning to be done and when it is needed there is no dust cloud to make the water cloudy. When your pump is off everything that enters your pool ends up on the bottom and stirred up when the pump starts.
I have tested this on my own pool and the requested customers to carry out the same test and the same results were observed. From the wiki link and average pool water is around 5 NTU's and a poor pool 10+ after several weeks of running my pool 24/7 which I now do for the whole summer the level of 1 NTU was obtained on my tester. The chlorine consumption fell although the sun still takes it's toll and the pH became more stable.

The reason we don't run our pumps for 24h? Cost and with the correct setup that issue can be put to rest too at least for domestic pools. I realise with the wide variations in pool water and temperature you have in the USA are different from Europe but I am sure that the pools will benefit form the extended run time. It is better to move the water constantly but slower than to move it rapidly for shorter time. Filters work much better with a slower flow so remove more but the downside of the 24h running is more frequent visits to empty the skimmer baskets proof that it works.

[mas985]

According to this web page collides are generally smaller than 1 um.This document also confirms that particles > 2 um will settle out in a few minutes but anything less than that will remain suspended indefinitely. At best, DE filter can only filter down to 5 um so any particles that are actually suspended in water, will not be filtered out anyway.