How much bleach should I plan to go through each week?

[jkrupp]

Hi, our pool is ALMOST done. We are in Northern CA and are going on month 5. The rains have been so heavy that there has been only one more day of work for months now. Hoping to have it plastered and filled next week.

The pool is 14' x 28'. It is only about 13,000 gallons, 3' to 6' depth. We have a family of 5 and I'm sure we will be using it at least 5 days a week all Summer. About how many gallons of bleach do you think I will go through with a pool this size, with almost-daily use?

I switched to the TFP method for my hot tub last year and LOVE IT!!! Has been 100% crystal clear since and not even a glimpse of "foam" (which the pool store always told me was from bathing suit detergent... hmm). But of course I only use a couple of TB every other day for hot tub Curious about the pool though.

 

[Mr Bruce]

There are a lot of variables including hours of sun, bather load, CYA, etc. If we were buying squares, however, I would like to buy the 3.5 gallons of 8.25% bleach/week square

 

[CJadamec]

I have roughly the same volume of water as you. With a cya of 40 and maintaining around 5 FC I was going through about 1.5 gallon of 12% a week. I kept the pool covered with a solar cover which lowers consumption. Bruce is probably pretty close at 3.5 gal in sunny California.

 

[jmastron]

It's going to depend a lot on the water temperature and CYA level you decide to maintain. At the default recommendation of 30-50, my pool nearby loses 3-4ppm/day when uncovered on a sunny summer day (almost all of them!). At CYA 70-80, I found it lost more like 1-2ppm/day. You can use https://www.troublefreepool.com/calc.html to figure out how much of a given concentration of chlorine/bleach is needed to raise it that much.

Personally, in this region I'd lean more toward a CYA of 60-80; that will reduce your chlorine use quite a bit without making it too difficult to SLAM if necessary (which it shouldn't be). You do need to maintain a higher FC level at that CYA, but the losses per day will be less.

 

[JoyfulNoise]

A clean and clear pool operating at TFP recommended FC/CYA ratio should lose no more than 4ppm FC per day (that's considered the high limit). So, if you were to lose that much chlorine each day in a 13,000 gallon pool, you will need to replace it by adding 77 fl. oz of 8.25% Clorox laundry bleach or 67 fl. oz per day of 10% chlorinating liquid. That's roughly 2 quarts per day or about 3.5 gallons per week.

The less loss you have, the less chlorine you will need to replenish. Being in California with hot sun on the pool every day, I would suggest you start at 40ppm CYA and see what kinds of losses you are getting. If your losses are near that upper limit, you should consider raising your CYA to as high as 80ppm to see if your losses get to an acceptable range. I would not go any higher than 80ppm CYA.

 

[CJadamec]

I like that there are 3 responses in 6 minutes saying the same thing. Both calculated values and real word usage of the method in such close agreement is pretty cool. Oh and jinx you two.

 

[jmastron]

Also, check whether buying HASA liquid chlorine in reusable jugs is cost effective and convenient for you -- from http://www.hasapool.com/dealer_locator_hasa.php, All Seasons Pool in Rocklin carries it. The place I get it from (All Clear Pool&Spa) has a buy-11-gallons-get-1-free card and summer coupons for 4th-gallon-free; with those the cost is lower than most of the other options I found.

This is 12.5% chlorine; comes in a 4-jug carrier. I think there was a $6 deposit the first time, now I just bring the empty set back, pay, and grab a new 4 gallons. In and out in 2 minutes. Less weight to lug home (because of the higher concentration), the jugs seem to pour smoother than most bleach bottles, in the carrier they don't tip over in the trunk, and I like not throwing away all that plastic. Yes, it involves going to a pool store, but I think they know that people buying liquid know what they're doing so at least at All Clear they are happy to sell it to me without any pressure or upsells. I reward that by buying poles, rakes, and such from them too...

 

[Mark R]

You guys are lucky with your bleach use. I go through 5/6 gallons a week at 70 cya. But, it is +-110 for almost 3 straight months. Solar gets it up to 85 too

 

[JoyfulNoise]

You guys are lucky with your bleach use. I go through 5/6 gallons a week at 70 cya. But, it is +-110 for almost 3 straight months. Solar gets it up to 85 too

An SWG might be a good alternative. I live in same place you do and I would not own a pool without an SWG. No way I'm hauling that much liquid chlorine around.


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[borjis]

I go through 1 gallon of generic 8.5% a week. CYA 50 and full sun for half the day. The pool is covered Mon-Fri until I get home around 6.
So it's fully exposed maybe for an hour on those days. But the solar cover is off all day sat-sun.

I do use another half gallon though if I have a lot of guests over on the weekend.

 

[jkrupp]

Thanks everyone! The pool does get full sun, all day/afternoon. But, I do plan to have it covered as well(I am a wimp when it comes to water temp). But you have given me a general idea, thank you!! I can't wait until it is finished.

 

[jmastron]

Thanks everyone! The pool does get full sun, all day/afternoon. But, I do plan to have it covered as well(I am a wimp when it comes to water temp). But you have given me a general idea, thank you!! I can't wait until it is finished.

A cover helps a lot here because even though it is so sunny and hot, it cools off a lot more at night than many places so we get a lot of evaporative cooling. I don't think the cover matters much during the normal sunny days, but at night it makes a big difference. Over the course of a week, our pool will get to about 10 degrees warmer than left fully uncovered; I can get into the 90s much of the summer before the kids complain that it's too warm and I have to leave it off for a couple nights.