How much chlorine should my pool be using?

How much chlorine should my pool be using if it's running properly?

It's a vinyl liner 18x36', deep end is 8' - I believe it is roughly 25,000 gallons.

Full sun virtually all day, cyanuric acid is 40-50 depending on whose test you believe, not sure of water temperatures but temps outside have been running high 80's to 100's.

A couple weeks ago I shocked and had chlorine levels over 15ppm for a couple days, but since then, both times chlorine has dropped below 5 or so, it seems like it drops like a rock from there - both times, it went from the 1.5-3 range to .5-1 in a day. After the first time, I shocked it back up to 15 for a day or so, but today it once again dropped down to .5-1.

Is this normal?

This evening, I just put in enough chlorine to raise levels up to 8ppm or so. Is that ok, or do I need to shock to 15ppm every time chlorine drops below minimum levels?

Also, it seems like FC and TC are virtually identical when I try to read them on the Taylor K-2005 test kit that came with the house (yes, the reagents are not out of date). Is that typical?

I'm slowly getting the hang of this thing, thanks for all your assistance!

How often are you testing? What is the cl when you test before adding bleach? How often are you adding bleach and how much?

Whether or not you need to shock every time you drop below range is not a hard and fast rule. Sometimes you can get away with too low of a cl reading briefly and other times you can't.

Test your pool again tomorrow morning within 2 hours of sunrise. If you have lost more than 1ppm of cl overnight, then you should shock the pool. If not, then it shouldn't be necessary.

I can't tell for sure from reading your post, but I kind of get the idea that you are maybe not testing regularly and as a result, your cl is getting too low. Is that right? I would suggest testing every evening for awhile and maybe even writing down your test levels in the evening, making notes of how much bleach you added and what level your cl was when you tested the next evening. This will help you identify a pattern with your pool. After a few days of doing this, if you find that you can make it two days without your chlorine dropping below 3ppm, then maybe you'll be able to test and dose every 2nd day instead of daily. You'll just have to learn how your pool behaves.

Is it normal to lose chlorine faster as the level gets lower? I can't say for sure, but I'd say probably. It makes sense that it would because once you get lower than the minimum chlorine requirement based on your CYA level, then something may start growing in the water and thus you'll use more chlorine fighting it.

When FC and TC are the same, that is good! That means you have no CC which you want to be 0 or at least no higher than 0.5. FC + CC = TC.

I don't know where you live but if you find after awhile that with a CYA of 40-50 you continue to have trouble keeping chlorine in your pool, then it may be appropriate to take it a little higher. Aylad (another one of the mods) lives in LA and her pool is in hot full sun all day. She deliberately runs her CYA at 80-90 (or maybe 70-80, I can't remember which) because without doing so, she can't keep a FC reading. This also allows her to only add bleach every second or third day instead of daily. Watch your pool's pattern for a few days and report back and we'll help you decide what is most appropriate for your pool.

Hope this helps.

I try to keep mine at 90. If it gets any lower than 70 or so, I have a hard time keeing a minimum in my pool, too.

Janet

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Originally Posted by Watermom

How often are you testing? What is the cl when you test before adding bleach? How often are you adding bleach and how much?

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The last week or week and a half, I've backed testing off to every other morning, and occasionally in the evening. Both times, I haven't added bleach until the chlorine level was down to the .5-1 range - I think each of those times, I tested two days before and had chlorine around 5 or 6, then a couple days later, dang near nothing.

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Originally Posted by Watermom

Test your pool again tomorrow morning within 2 hours of sunrise. If you have lost more than 1ppm of cl overnight, then you should shock the pool. If not, then it shouldn't be necessary.

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How should I be testing? My OTO and Taylor K-2005 test kits only test chlorine up to 5, so I have to measure and dilute the water, swirl in a measuring cup and then pour to get a reading, which is extra steps and added inaccuracy. The Brita pitcher and my tap both dispense chlorinated water - do I need to buy distilled or bottled or what? For instance, tonight all I had was tap water, which tested at .6ppm on my OTO, so diluting with that guaranteed my readings to be inaccurate. Will a better test kit go to higher levels?

Between that and my inability to always tell what color the test corresponds with on the scale on the Taylor kit (the OTO chlorine test is easy to read, the Taylor I have a little more trouble discerning on), my testing isn't accurate.

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Originally Posted by Watermom

I can't tell for sure from reading your post, but I kind of get the idea that you are maybe not testing regularly and as a result, your cl is getting too low. Is that right? I would suggest testing every evening for awhile and maybe even writing down your test levels in the evening, making notes of how much bleach you added and what level your cl was when you tested the next evening. This will help you identify a pattern with your pool. After a few days of doing this, if you find that you can make it two days without your chlorine dropping below 3ppm, then maybe you'll be able to test and dose every 2nd day instead of daily. You'll just have to learn how your pool behaves.

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Originally Posted by Watermom

I don't know where you live but if you find after awhile that with a CYA of 40-50 you continue to have trouble keeping chlorine in your pool, then it may be appropriate to take it a little higher. Aylad (another one of the mods) lives in LA and her pool is in hot full sun all day. She deliberately runs her CYA at 80-90 (or maybe 70-80, I can't remember which) because without doing so, she can't keep a FC reading. This also allows her to only add bleach every second or third day instead of daily. Watch your pool's pattern for a few days and report back and we'll help you decide what is most appropriate for your pool.

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I'm in south central Kansas, it's frequently hot and sunny. I was trying to avoid high CYA, since then the little OTO test would still show chlorine off the charts even when it's below the necessary minimum levels on the Best Guess Chart. How do they deal with that? Just buck up and take extra steps to test? Am a little hesitant to add CYA since reversing it is so dang difficult, but I guess I'll watch and see.

If you are going to do the dilution method, you need to buy some distilled water.

Better yet, go ahead and get a good test kit. We recommend the Taylor K-2006 or 2006C. But, since you already have the K-2005, you don't need to purchase the entire kit. You can just buy the K-1515 which will give you the component that your kit is missing which is the FAS-DPD. That is the part of the test that allows you to test high chlorine levels. You can find it in the Amazon link in my signature.

Best to test in the evenings after the sun is off the pool and don't ever let your chlorine get that low. Unless you like algae!! :eek:

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Originally Posted by Watermom

...I don't know where you live but if you find after awhile that with a CYA of 40-50 you continue to have trouble keeping chlorine in your pool, then it may be appropriate to take it a little higher. Aylad (another one of the mods) lives in LA and her pool is in hot full sun all day. She deliberately runs her CYA at 80-90 (or maybe 70-80, I can't remember which) because without doing so, she can't keep a FC reading. This also allows her to only add bleach every second or third day instead of daily. Watch your pool's pattern for a few days and report back and we'll help you decide what is most appropriate for your pool....

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Originally Posted by DistantHorizon

The last week or week and a half, I've backed testing off to every other morning, and occasionally in the evening. Both times, I haven't added bleach until the chlorine level was down to the .5-1 range - I think each of those times, I tested two days before and had chlorine around 5 or 6, then a couple days later, dang near nothing.

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Watermom hits the nail on the head. I have a CYA range similar to yours. I lose about 2.5 ppm FC per day. Your pool seems to behave the same as mine. With a CYA like yours and mine, we have to stay between 3-6 ppm of FC. We can't go below 3 but it's alright to go a little over 6.

You don't have to test everyday and you don't have to add chlorine everyday. I add chlorine everyday and I'll explain why. Let's say we want to make 4ppm as our lower limit and that's what our test says we have in our pool on Monday evening. To make it to Wednesday evening, I'll have to add at least 5ppm because I lose 2.5 ppm per day. That means there will be 9ppm of FC in the pool Tuesday morning. That's not a real problem with CYA near 50 but I have little guys that like to swim early in the morning. I would have no problem letting them swim with 9ppm but it's no trouble for me to add 2.5ppm every evening. That puts me at 6.5ppm. That's enough wiggle room if the wee ones weedle in the pool.

Right now it looks like you have to add a gallon of 6% Bleach a day or 2 gallon every other day. Don't do like I did last year. Get the FAS/DPD kit to test chlorine. Believe me, it will pay for itself and save you from a lot of headaches. With this kit you'll be able to get your pool patterns down pat. When or if you have to shock, you'll know exactly where your at and exactly when to come out of it.

Ok, well, I ordered the FAS-DPD test kit ( http://www.amazon.com/gp/product/B003V54GUG ), but it won't be here until Wednesday. Also ordered more CYA test ( http://www.amazon.com/gp/product/B0002IXIZE ).

In the meantime, with the expectation that I'll have to add CYA, and knowing that the pool uses chlorine, I put a dozen 3" tabs in the skimmer basket (knowing they take several days to disolve). Ran the pump continuously with tabs in for about a day, with the plan to remove the tabs when pump was off.

Was time to backflush last night (my spider gasket was still jacked, and pool guy hadn't dropped by yet), backflushed and rinsed. Took apart the multiport, tried to reseat gasket, got things working though backflush hose was still trickling.

Checked chlorine and CYA last night (diluting 50% with distilled water), read 2-4 on the scale, so figured it was 5 or 6. Knew that tends to drop, so took out tabs, disolved a pound of dichlor in a bucket and put it in (for target of 8, and to add a little CYA). Hooked automatic pool cleaner to the skimmer and let it run overnight.

This morning I went to get a spider gasket, and took a sample to a pool store who I at least think knows how to test properly. Chlorine was 8 (which was what I'd targeted), but they said CYA is over 100!

:(
:(
:(

She let me see the test for myself (they had the more expensive dipstick-in-tube test).

In the past, one pool store has tested it at 100+ 3 times, 30 once, and 40 once. When I tested last night, I read about 42, which corresponds with the 40 I read a couple weeks ago (I have the Taylor K-2005 CYA test), but as with all the color-match tests, I wasn't completely confident I was reading it right. The previous pool owner appears to have used 3" tabs and dichlor exclusively, which would point to high CYA.

I just did my own test again, and got a little higher reading, 45, than I did before I added dichlor and tabs, so if I'm misreading, I'm doing so consistently.

Question one: Did CYA test high because I've been adding it recently (added dichlor the night before, and ran 12 3" tabs for a day before that)? Or is my CYA really that high???

Question two: Edit - researched on this forum, indeed I did get pool-stored. Going to try to return this stuff, no need to answer this question. The pool store said my phosphates are 300, and that could be eating my chlorine. Is that true? I didn't think fast enough, and got pool-stored into a $40 jug of phos-free, but I haven't added it yet. Don't know if I can return it or not...

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Originally Posted by Yeggim

Right now it looks like you have to add a gallon of 6% Bleach a day or 2 gallon every other day. Don't do like I did last year. Get the FAS/DPD kit to test chlorine. Believe me, it will pay for itself and save you from a lot of headaches.

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Gah, all that bleach sounds like a lot of $, but if that's what it takes, then that's what it takes. We'll have to see how my CYA issue turns out. As for the kit, yeah, went ahead and ordered.... wish I'd ordered a better CYA test rig too.

Don't panic. Your CYA test is more likely to be accurate than their dipstick-in-tube test. The disappearing black dot test is the only one we trust.

So, if you are getting 45ish for your CYA reading, assume that is correct. What goal are you shooting for? Typically we suggest 40-50. if that is what your target is then remove all pucks from your pool and also don't use any more dichlor. A week after the last dose of any stabilized chlorine, test your CYA again, but not before. Then, post a full set of numbers here and we'll make a recommendation for you from that point.

The saga continues! On a positive note, the pool store took back their silly Phos Free, so that's $40 back in my pocket.

Went to another pool store where CYA scored a 70! Apparently I can get whatever numbers I'd like just by getting different people to test, lol! Chlorine had dropped a whole ppm, from 8 @ 9am to 7 @1:30pm, part of which I might write off to testing inaccuracies.

I guess irregardless, my pool IS running fairly well. I seem to lose a lot of water to evap, and it seems to get a lot of dirt in it; but water has been clear for IIRC, a couple weeks now.

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Originally Posted by Watermom

Don't panic. Your CYA test is more likely to be accurate than their dipstick-in-tube test. The disappearing black dot test is the only one we trust.

So, if you are getting 45ish for your CYA reading, assume that is correct. What goal are you shooting for? Typically we suggest 40-50. if that is what your target is then remove all pucks from your pool and also don't use any more dichlor. A week after the last dose of any stabilized chlorine, test your CYA again, but not before. Then, post a full set of numbers here and we'll make a recommendation for you from that point.

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I don't know what I should be shooting for. I figure I can shoot for 45-50 or 70ish, but I don't know which. I am uncertain of which will be cheapest. I wouldn't mind running higher levels, but it seems that shocking would be fairly expensive and hard on swimsuits.

I will not add any more CYA (though I lost a little this morning to a fairly long backflush) for another week, and I'll post numbers with my brand new CYA reagent bottle.

Losing 1ppm if it was really sunny wouldn't be unusual. You're gonna lose chlorine and that is fine. CYA helps protect it but losing it during the day is to be expected. Plus, as the chlorine does its job of sanitizing the water, it is also depleted.

If our CYA is 45ish, I'd leave it there for now. If you find that you can't keep chlorine in the pool, you can always add more. Don't bother having anyone else test it for you. YOU will do a better job than any pool store. As far as having to shock harder --- you use more chlorine at a time but don't have to add it as often so it balances out. And, high chlorine with high CYA is not any harder on swimsuits than low chlorine and low CYA. It is the same.

Jun 25 morning, FC 8, pH 7.4
Jun 25 evening, FC 7

Jun 26 morning, FC 6, pH 7.2, TA 110
Jun 26 evening, FC 5+ (didn't bother to dilute), pH 7.2

Jun 27 evening, FC 5, pH 7.2; added 52oz 6% bleach for target FC 6
Jun 28 evening, FC 5, pH 7.3/7.4; added 52oz 6% bleach for target FC 6

On Jun 29, I received my FAS/DPD test kit! Also new CYA reagent, but it hasn't been a full week since adding stabilized chlorine.

Jun 29 evening, FC 5.5, pH 7.6, CC maybe .5; added 2.5oz cal hypo for target FC 6/6.1

Jun 30 evening, FC 4.5, pH 7.4, TA 110; added 7oz cal hypo for target FC 6.1.

Since I've been uncertain about CYA, I made the decision for now to just try to keep FC between 5 and 6, since 5 is above the minimum on the the 60-90 range of the Best Guess chart.

What do you all think about these numbers? I guess the only thing I notice in looking over them is that FC dropped quickly again from Jun 29- Jun 30... but I'm thinking maybe the Pool Calculator's 2.5oz recommendation was a little low.

Thanks again for all the help.

Your numbers look fine. Post your CYA level when you test for it.

Well, in the last week or so, I've been very busy and also had the pump motor quit midway through the holiday weekend, so my chlorine numbers have been irrelevant and jumped all over the board (I kept it high with liquid bleach during the few days where it wasn't circulating); but I tested my CYA just now, and I'm sticking to my guns - it's around 45 or so, about like it tested with my old reagent.

Have been doing my best to keep chlorine at 5 or above for a while now, but it looks like I can back that down to 3+ since I'm more confident CYA is at MY test results, and not the pool stores.

I noticed the Best Guess Chlorine Chart has blank areas - nothing between 20-30, 50-60, and 90-100... I assume those are just subjective gray areas?

Not sure whether to run CYA up higher or not - it sounds like the amount of sun I get would support higher CYA, but then when I shock people can't swim for a while. I'd hate to be the guy whose pool wasted a bunch of swimsuits in one day.

Stay with CYA of 45 for awhile and see how it goes. When you test in the evenings, add enough bleach to take the cl back up to around 6. See if you stay above 3 by the time you test the next evening. If you consistently find that you can't, take it up to 7. If that still doesn't keep you at a minimum of 3 by the next evening, then at that time, you can decide that you may want to bump the CYA up a little.

BTW -- High CYA/High Chlorine is no more damaging to swimsuits than Low CYA/Low Chlorine.

Actually the chart shows 10-20, 30-50, 60-90, 100-200

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Originally Posted by Watermom

Actually the chart shows 10-20, 30-50, 60-90, 100-200

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That's what I mean... say you have CYA 55, the chart doesn't have a recommendation for it... so I figured those were areas where you just have to see what happens with your specific pool, deciding whether to follow the higher or the lower recommendation.

To be on the safe side, I just go to the higher category.