Domestic pool turnover rates

[CarlD]

The math doesn't add up. I run my pool at low 12hrs a day solely to keep my solar panel decking cool and the water warm. Running it 24/7 will NOT save me money, it will cost money. You are not understanding Mark's point.

Different ideas have to be proven before we allow them given as advice here. And many have been, including, for example, SWCGs, high borate levels, and TA levels below "standard range" to name a few. But they all have been proven, not merely asserted.

If you want to continue this, take it to the China Shop until you can prove it.

[Anonymous [GDPR] European in the UK]

Carl, I do understand Mark's point. Mark has been terrifically helpful over the years with the information he has passed on to me. Without that information it would have taken a lot longer and cost a lot more in research.

I know at the moment it doesn't seem logical to you to run 24 hours a day but rather than go around in circles can we put some facts and figures down? I don't know the cost of electricity where you are so that would be useful.
How much electricity per hour do you use on low speed?
Do you know your actual flow rate on low?
What is the flow rate needed to run your heating (min flow)

If the electrical energy used for 24 hour running is less than you use for 12 hour running that would still be a saving, yes?

On a separate note: I didn't know running low TA levels was ok on the pool forum, I have been doing the same over in the UK and France as it didn't make any sense to run at a high TA (Vinyl pools only) currently run at TA 40ppm with very stable pH. I have a customer who is running around 22ppm TA as their water is really soft in that area still no bad effects and very stable pH.

If you would prefer to move the thread to the china shop I am OK with that if it's the proper place but I don't just want the topic to gather dust.

[CarlD]

I have moved this to the China Shop.
My low speed setting runs around 1/4 hp vs the 1hp full speed. My solar panels cannot be opened more than a crack at full speed because they will distort and leak, but at low can be opened all the way.

There is no possible way running at low speed for 24 hours will NOT use double the KWH of running at low speed for 12 hours.

Personally, I see Mark's point as being what is NEEDED to distribute chems evenly and actually filter the water. It doesn't take into account ancillary needs like skimming the surface, aerating to raise pH without raising TA, sufficient run time for an SWCG, or solar panels. Nor does he claim it does. He merely claims that a full daily turnover of water isn't really necessary.

As for cost savings, usually 2speed pumps can run far longer and more efficiently. Even if we go back to the touchstone of one turnover per day, what is the point of a 24/7 run unless your pump is 'way too small for your pool? If I can turn over my water at low in 10-12 hours, why run it doubly long? If I can turn it over in 6 hours at high, I will still use double the KWH of a turnover at low. You cannot magically squeeze more electricity out of a pump by running it twice as long AT THE SAME SPEED!

TA is a buffer for pH. I cannot explain the full chemistry of Carbonic Acid and Bicarbonate ions, as I leave that to my son, the Chem major and Chem_Geek. But generally, if pH tends to trend up, keeping TA lower can slow or arrest that. Likewise if pH tends to trend down, higher TA also controls that. And, if you have a vinyl pool and your pH is stable, TA is only important if it approaches 200ppm with a CH of 400ppm or more, because you can get cloudy water and scaling.

Since I rebuilt my pool my TA has been trending high, around 170 (local water). pH has been trending down, but that's been due to two floaters filled with Tri-Chlor tabs, which are acidic, but keep FC up and add CYA. Been compensating with low doses of Borax, so pH has stayed at 7.3-7.4. But in the past, even last season, TA was at 50-60 with no problems.

[Anonymous [GDPR] European in the UK]

Hi Carl,
Ok your running at 1/4hp, on a pool pump with plumbing and filtration load I would guestimate that is using 280 watts per hour x 12 hours = 3.36kw per day
I don't know your flow rate but again a guess at that level 38 GPM.

My system is built to be super efficient and I know if your flow rate less than 22 GPM then the skimming action on the surface is not good enough with a skimmer but it could still work with an infinity edge.
My pool runs at 23GPM overnight (16 hours) and when swimmer are in the pool 26 GPM (8 hours) but the total electricity per day is just 960 watts 0.96kw.

The reason for 24 hour running is that I have many trees and also we are in a farming area so debris is usual, if the pump isn't running this debris gets water logged and sinks, some people spend $100's on pool robots, if they spent that upgrading the system they wouldn't need the robot, I sold mine a few seasons ago. If the pump is running it gets skimmed off and the water stays cleaner.

I wish Marks report was more scientific, with proper turbidity test carried out and a particle count to see what was really in the water. If the pump is off the debris sinks but it doesn't show until it's stirred up. Since doing this the water is much clearer 0.5-1 NTU and there is no dirt or debris to stir up.

What Marks report does show is how little is really needed to keep the water in condition, too many people hung up on turnover rather than brilliant filtration which actually removes the dirt not just recirculates it.
Gage and Bidwell's paper on water turnover and dilution says after 1 turnover 63% of the water has been filtered, by my action I get a 6 hour turnover and that filters 4 times in 24 hours so 98% of the water is filtered. I am reducing the speed of my pump to just the 23 GPM for the full 24 hours as that will give just less than 3 turnover rates and 95% of the water filtered on 0.84kw of electricity and I will see if that makes any difference to the water quality. At that flow it should still be sufficient for a heat pump to run (just) but likewise a good solar setup may need a bit more push if it's not that well made but these are terrific energy savings.

There is very little leaf collecting or pool vacuuming to do compared to short running that I used to do.

Regards
John

[mas985]

I wish Marks report was more scientific, with proper turbidity test carried out and a particle count to see what was really in the water. If the pump is off the debris sinks but it doesn't show until it's stirred up. Since doing this the water is much clearer 0.5-1 NTU and there is no dirt or debris to stir up.

The study seems pretty clear to me which states that they SAW no observable difference in water quality after 2 hours. If the debris sinks, then a vacuum can easily remove it without "stirring it up". The only time I have heard of someone having an issue like you are describing is when they just killed a bunch of algae and it sunk to the bottom. That debris is very light weight and can be stirred up easily but when cleaning up algae after it is killed, you should be running 24x7 anyway. But that should not happen very often if you follow the methods taught here.

As I said chlorine will kill what in can in under a minute, that would be lots of different bacteria, virus's etc including algae spores so that's the job done except for chlorine resistant types, like Giardia and Cryptosporidium and oocysts which need filtering out (this depends on the filtration being good enough and may also need flocculent. Generally the pumps are too big and the filters too small to achieve great filtration, eyesight is too bad to judge.

Why only a minute? Chlorine does not stop killing after one minute, it should continue killing these things if the level is set properly.

Gage and Bidwell's paper on water turnover and dilution says after 1 turnover 63% of the water has been filtered, by my action I get a 6 hour turnover and that filters 4 times in 24 hours so 98% of the water is filtered.

So what? Again, there is no good reason to filter the water at any specific turnover rate. It just doesn't matter to sanitation. Aesthetics, perhaps but only to some.

What considerations would increase that run time? We have debris from out arbor vitae trees falling into the pool all the time, and we can't be out there manually skimming all the time. Would just 2-4 hours per day on high be enough and then a good chunk more on low be OK?

Removing floating debris and debris that has sunk to the bottom of the pool is entirely up to you. It is only based on your personal preference.

Some people like me could care less if there is a little debris in the bottom of the pool or even on the surface. My priority is to minimize run time.

Other people are quite anal about a pristine pool and thus require lots of run time so every spec of dirt and debris are immediately removed from the pool. However, this desire sometimes comes at a large cost.

[CarlD]

I, for one, like a pristine pool. See above ^^^

But as I pointed out that is NOT Mark's point. My reasons for running longer than is necessary for sanitation are valid, but not relevant to his point. They are separate issues.

[Anonymous [GDPR] European in the UK]

The study seems pretty clear to me which states that they SAW no observable difference in water quality after 2 hours. If the debris sinks, then a vacuum can easily remove it without "stirring it up". The only time I have heard of someone having an issue like you are describing is when they just killed a bunch of algae and it sunk to the bottom. That debris is very light weight and can be stirred up easily but when cleaning up algae after it is killed, you should be running 24x7 anyway.

Yes but the human eye can't see very much, if anything smaller than 30 microns. You cant see electricity so is that safe then? Although thankfully rare chlorine resistant strains of bacteria do happen so filtering them out is necessary and if you filter at that level very little chlorine or chlorine reactions are needed to keep the pool in top condition. If what I wrote was more expensive than normal I could understand the objection but I achieve these results on a lot less, call it a bonus.


Why only a minute? Chlorine does not stop killing after one minute, it should continue killing these things if the level is set properly.
Now that is a miss understanding, chlorine doesn't stop killing of course but it can terminate most common bacteria and virus etc in under a minute. That's why when the level of chlorine present is sufficient then high filtration rates are not needed as the report also showed. In fact because most people have pumps to big for there filters they are wasting more electricity breaking up whats filtered into smaller parts that just pass through the filter.



So what? Again, there is no good reason to filter the water at any specific turnover rate. It just doesn't matter to sanitation. Aesthetics, perhaps but only to some.
Yes agreed, I just made observations about the rate Not a recommendation.



Removing floating debris and debris that has sunk to the bottom of the pool is entirely up to you. It is only based on your personal preference.

Some people like me could care less if there is a little debris in the bottom of the pool or even on the surface. My priority is to minimize run time.
My priority is to minimise electricity bills, and cleaning all the other parts come as a bonus. My pool is let to paying guests they can be quite anal.

Other people are quite anal about a pristine pool and thus require lots of run time so every spec of dirt and debris are immediately removed from the pool. However, this desire sometimes comes at a large cost.

[CarlD]

Teapot:
Are you a commercial pool operator? "My pool is let to paying guests..." makes me infer that you are.

Anyone in the pool business is required to very specifically state that in their signature. If you are in the business of SELLING "Passivpool" then you must explicitly say so. If you are not and are merely singing its praises in your sig, that's OK.

But again, if you are a commercial pool operator or in the pool biz you must say so--and abide by our AUP for pool pros.