Normal Amount of Chlorine / Acid to Use in a Year?

[LarryFlorida]

Hello-

Thank you for indulging in what is probably a very basic question for you all, but will help me understand how I am doing with my pool maintenance.

I know that you need alot of background info to help answer questions, so here are the basics.

I have an ~20,000 gallon inground pool and a ~600 gallon in ground hot tub. They are separate such that each is treated independently. Both are concrete and have a quartz type surface. I cant remember the brand name of the surface but its one of the newer types that is slightly rough (not the marcite type, but not the pebbletec type either)

For treatment over the past 14 months, I have been using an Eclipse 4 ozone generator on the pool and an Eclipse 1 ozone generator on the spa, along with supplemental chlorine and acid. The ozone is injected into the inlet of the pump.

The pool and spa are heated via solar panels (10 panels for the pool and 2 for the spa, each panel is ~50 sq ft). The pool has a 2hp pump which runs 9 hours a day with a DE filter and the spa also has a 2 hp pump which runs, on average, 6-7 hours a day and uses a 150 sq ft cartridge type filter. (The spa pump is controlled by the solar system such that if heat is available, the pump runs.) There is also a 3/4" booster pump for the pool cleaner which runs ~3 hours a day as the cleaner is the type driven by pressure not suction. The pool temperature runs ~95-97F in summer and ~72-74F in winter.

The pool has looked fantastic during these 14 months and Ive had no issues at all. I try and keep the chlorine levels as low as possible (as in ~1 ppm or so). This seems to be working with the ozone, but I am not sure if the chlorine is actually doing all the work and the ozone is just "fluff".

So, to help answer that question-----

For a pool and spa of this size, in a 12 month swimming season environment, about how much chlorine should I expect to be using?

Ive kept track of my usage, and in ~14 months Ive used ~38 lb of 3" chlorine tablets and ~6 jugs of liquid chlorine. The tablets are added via a floating dispenser, and I just dump some liquid in periodically if the level drops too low (to give the pool a quick boost).

Is that about what one should expect to use in a pool like this regardless of whether or not ozone is on the pool? In short, is the ozone cutting chlorine usage down, or is it just another (expensive) box hanging on the the wall? I have no complaints on the water quality with the regimen I have been using, I am just curious as to how much of the water quality is due to chlorine and how much is due to the ozone.

Thanks for the guidance.

 

[LarryFlorida]

I forgot to add I have used ~8 jugs of acid in this same time period as well. Is that about normal? The pH definitely wants to run to 8.0-8.2 and I try to keep it in the mid 7's.

 

[duraleigh]

Impossible to say really accurately but an outdoor pool with an average swimmer load seems to use 1.5 - 2ppm daily of chlorine.

Out of curiosity, how are you testing your chlorine and how are you adding it to the pool?

 

[LarryFlorida]

Impossible to say really accurately but an outdoor pool with an average swimmer load seems to use 1.5 - 2ppm daily of chlorine.

Out of curiosity, how are you testing your chlorine and how are you adding it to the pool?

Thank you for the reply.

I am testing just using a basic test kit (cant remember brand) with periodic samples brought to Leslie's Pool for correlation.

 

[linen]

Welcome to tfp, LarryFlorida

Ozone use in a Pool:
We do not recommend using ozone on a typical residential outdoor pool. Ozone can actually cause a higher demand of chlorine since it can destroy the chlorine in the contact chamber. The other problem with using ozone and low levels of chlorine is that the residual sanitizer (chlorine) level in the pool water may be too low to prevent algae. The ozone only kills what goes through it's chamber. If the chlorine level drops close to zero, then there will be no protection from person to person transmission of disease.

Ozone use in a Spa:
Here ozone can be helpful if you are using Bromine as your sanitizer, since it will activate Bromide into Bromine (a sanitizer).

As for the acid usage, we need to know more about your pool such as TA, and if you have any features that aerate the water such as jets, waterfalls etc. Also is your "plaster" 14 months old? New "plaster" can also drive acid use.

For a pool and spa of this size, in a 12 month swimming season environment, about how much chlorine should I expect to be using?

This hard to estimate...since each pool is different.

The place to start is to post a full set of test results. See: http://www.troublefreepool.com/what-we-need-to-know-to-answer-your-questions-t10341.html

 

[duraleigh]

I try and keep the chlorine levels as low as possible (as in ~1 ppm or so)

That would seem pretty difficult, virtually impossible, without an FAS/DPD test. How are you adding the chlorine to your pool and in what dosage?

 

[LarryFlorida]

I try and keep the chlorine levels as low as possible (as in ~1 ppm or so)

That would seem pretty difficult, virtually impossible, without an FAS/DPD test. How are you adding the chlorine to your pool and in what dosage?

I am sure the levels are bouncing around somewhat so I dont really know that I am holding ~1ppm all the time. To be honest, I dont test it very often (maybe once or twice a month in winter and perhaps 2 or 3 times a month when the water is warmer), as the water more or less take care of itself. I do sometimes get a reading that is 2,3,4 ppm, and if that happens I just dont add any chlorine for awhile until I see its dropped to ~1ppm or so. Perhaps not the most precise approach! But, I havent had any problems and its easy.

As for how the chlorine is added, I just use a floating tablet deal that sits in the water. I also add liquid once in awhile if I think the chlorine level is too low (to bring it up quickly.)

 

[duraleigh]

OK. Since your chlorine usage is not tracked very well, I think what you are asking is if the ozone is doing you any good. The consensus on the forum is not very much at all in an outdoor pool. Indoor pools benefit but it is not very useful at all in an outdoor pool.

After all that, you seem to have found a maintenance program that is working well for you so I wouldn't change anything.....don't fix it if it ain't broke. :-D

 

[linen]

I am sure the levels are bouncing around somewhat so I dont really know that I am holding ~1ppm all the time. To be honest, I dont test it very often (maybe once or twice a month in winter and perhaps 2 or 3 times a month when the water is warmer), as the water more or less take care of itself. I do sometimes get a reading that is 2,3,4 ppm, and if that happens I just dont add any chlorine for awhile until I see its dropped to ~1ppm or so. Perhaps not the most precise approach! But, I havent had any problems and its easy.

I am not trying to be offensive...but I personally would not swim in your pool.

We advocate accurate and timely testing on this site in order to keep pools trouble free. Once the methods taught on here are learned, then it becomes quite easy to know what your pool chemistry is and properly adjust it.

Let us know if you want more help. This pool school article might be a good place to start: http://www.troublefreepool.com/pool-school/types_chlorine_pool

 

[LarryFlorida]

Welcome to tfp, LarryFlorida

Ozone use in a Pool:
We do not recommend using ozone on a typical residential outdoor pool. Ozone can actually cause a higher demand of chlorine since it can destroy the chlorine in the contact chamber. The other problem with using ozone and low levels of chlorine is that the residual sanitizer (chlorine) level in the pool water may be too low to prevent algae. The ozone only kills what goes through it's chamber. If the chlorine level drops close to zero, then there will be no protection from person to person transmission of disease.

Ozone use in a Spa:
Here ozone can be helpful if you are using Bromine as your sanitizer, since it will activate Bromide into Bromine (a sanitizer).

Thank you for the welcome.

As for how the ozone gets injected-----

Originally I was using the venturi injector deals to add the ozone after the filter. But, I switched it after a short while to instead have the ozone be drawn into the pump suction basket so that it gets all churned up in the water and has alot more time to sanitize the ater (and presumably the filters). When I made this switch, I think the ozone became more "useful" as I no longer get any trace of the ozone smell at the pool jets. So, I am assuming the ozone has all gone to O2 from O3?

To get rid of that 03/02 gas in the filter, I have a vent line and hose section from the top of each filter which runs back to the old venturi injector (where the ozone was originally injected). So, I assume any residual ozone left then gives a second "hit" on the circulating water (although I am not sure if there is any 03 left at that point). But, in the least it makes sure the filters stay efficient (and the top half of the filter housings arent just filled with gas).

I originally was worried about using this approach (as I thought the ozone might ruin the pump or filters, etc), but Ive been doing it for over a year and nothing has changed, so I guess the ozone concentration in the water even at the pump basket is not high enough to cause any harm.

As for the spa, I switched it to chlorine from bromine the same time as all these other changes were made. It was just easier to not have to buy bromine and chlorine, etc and also allows me to move water from the spa to the pool. In fact, to keep the spa water fresh, whenever I need to top the pool off with water, I just pump the spa to the pool and then refill the spa. Ive read that spa water should be changed about every 3 months, and this method allows for better than that. I do get alot of evaporation of the pool, so I am adding water fairly frequently.

 

[LarryFlorida]

OK. Since your chlorine usage is not tracked very well, I think what you are asking is if the ozone is doing you any good. The consensus on the forum is not very much at all in an outdoor pool. Indoor pools benefit but it is not very useful at all in an outdoor pool.

In a nutshell....yes.

Does the ozone save on chlorine usage?

I dont have another pool to compare to........

 

[LarryFlorida]

I am sure the levels are bouncing around somewhat so I dont really know that I am holding ~1ppm all the time. To be honest, I dont test it very often (maybe once or twice a month in winter and perhaps 2 or 3 times a month when the water is warmer), as the water more or less take care of itself. I do sometimes get a reading that is 2,3,4 ppm, and if that happens I just dont add any chlorine for awhile until I see its dropped to ~1ppm or so. Perhaps not the most precise approach! But, I havent had any problems and its easy.

I am not trying to be offensive...but I personally would not swim in your pool.

We advocate accurate and timely testing on this site in order to keep pools trouble free. Once the methods taught on here are learned, then it becomes quite easy to know what your pool chemistry is and properly adjust it.

Let us know if you want more help. This pool school article might be a good place to start: http://www.troublefreepool.com/pool-school/types_chlorine_pool

Well then I wont invite you over for a poolside BBQ! LOL

hehehehehehee

In any case, Ive seen nasty pools that I wouldnt swim in either. Mine, no joke, is crystalline and its used almost daily (and no sicknesses....LOL). So, I suspect the overall santition is adequate its just a matter of knowing whether or not the ozone is providing useful benefit, or if the chlorine is doing 99% of the work......

Perhaps I should peruse the quoted article.

 

[linen]

Well then I wont invite you over for a poolside BBQ! LOL

hmmm...but I really like BBQ (ugly drum smoker here)...if I changed my mind about the swimming, could I still come over :-D

 

[LarryFlorida]

I am sure the levels are bouncing around somewhat so I dont really know that I am holding ~1ppm all the time. To be honest, I dont test it very often (maybe once or twice a month in winter and perhaps 2 or 3 times a month when the water is warmer), as the water more or less take care of itself. I do sometimes get a reading that is 2,3,4 ppm, and if that happens I just dont add any chlorine for awhile until I see its dropped to ~1ppm or so. Perhaps not the most precise approach! But, I havent had any problems and its easy.

I am not trying to be offensive...but I personally would not swim in your pool.

We advocate accurate and timely testing on this site in order to keep pools trouble free. Once the methods taught on here are learned, then it becomes quite easy to know what your pool chemistry is and properly adjust it.

Let us know if you want more help. This pool school article might be a good place to start: http://www.troublefreepool.com/pool-school/types_chlorine_pool

Well then I wont invite you over for a poolside BBQ! LOL

hehehehehehee

In any case, Ive seen nasty pools that I wouldnt swim in either. Mine, no joke, is crystalline and its used almost daily (and no sicknesses....LOL). So, I suspect the overall santition is adequate its just a matter of knowing whether or not the ozone is providing useful benefit, or if the chlorine is doing 99% of the work......

Perhaps I should peruse the quoted article.

Ok...just read the short article and the thought is just use liquid.

This is easy.

Now, how much liquid is one going to need typically? It seems like unstabilized chlorine (liquid is unstabilized I believe?) would need to be added very frequently?

 

[LarryFlorida]

I just went out and using my basic test kit was able to ascertain the pool water right now is ~3 ppm free chlorine, 7.8 pH and total alkalinity of ~50.

So, I suspect I am not running, on average, the ~1ppm I perhaps am targeting. In reality I suspect the average is something more......

 

[linen]

Do you have the ability to measure cya? If your cya is high (which I suspect it is due to your puck use), then 3 ppm FC is not very much.

 

[jblizzle]

Also read about the CYA/FC relationship in Pool School. All those pucks you have used have added stabilizer which does not get consumed liked the FC. So your pool likely is plenty if not overly stabilized.

While your approach appears to be working, you very well could be just holding algae at bay and if the stabilizer continues to rise, the low FC levels will not be effective enough.

Posted from my Droid with Tapatalk ... sorry if my response is short

 

[LarryFlorida]

Do you have the ability to measure cya? If your cya is high (which I suspect it is due to your puck use), then 3 ppm FC is not very much.

My basic kit cant read CYA, but I just looked at the last Leslies pool water sample test and it showed 50. The "acceptable range" on their sheet says "30 to 99".

Do I want to run on the high end or low end of the range? And, is what they are saying is "acceptable range" accurate?

 

[jblizzle]

Historically, the CYA test seems to be the one that pool stores are the worst at. We generally do not trust any pool store testing, especially for CYA.

If you really want to understand your pool, order one of the recommended test kits.

Posted from my Droid with Tapatalk ... sorry if my response is short

 

[LarryFlorida]

You made me go look at a bunch of the past test reports!

The CYA on them does vary somewhat. On the 5 or 6 reports I looked at they ranged from 45 to 60. Is that normal range of variability? It was not necessarily the same person doing each test, so I suspect some differential?

I dont know alot of about the test kits, etc, but I looked at the system Leslies uses and it appears to have alot of bottles, etc and it is made by Taylor (which from my little bit of research appears to be a respectable brand).