no chlorine

Chlorinating, maintaining the right chlorine levels,
chlorine problems. Dichlor, trichlor, cal hypo, bleach,
granules, chlorine pucks and chlorine sticks.
Dandle
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Postby Dandle » Fri 15 Jun, 2007 16:28

Have just found this site after having a problem with my pool going cloudy due to not having enough chlorine in it. After adding some chlorine and it not registering I added some shock granuals which didnt register so I was told it was probably in chlorine lock. I then bought some chlorine liquid to shock it again which didnt work. I was at the end of my tether when I found this site and saw the post on too much chlorine causing a bleaching affect on the test pills. I diluted the water down by 5 times in a jug and the chlorine registered. I have now added way to much by the looks of it so will let it burn off now. Just wanted to say thanks to everyone in this post, I have learnt alot.


spike

no free chlorine, low total chlorine

Postby spike » Fri 22 Jun, 2007 21:46

we've had difficulties maining the chlorine levels in our 22,000 gallon in ground pool. teated for phosates last fall while winterizing the pool, 1000 points before teating. opened the pool 3 weeks ago still having issues with the cholrine levels, free and total. tested for phosphates levels at 500 points. treated again still low chlorine levels. tested for phospates today, 2500 points. CYA 85, ph 7.0, alkalinity 180. using an auto chlorine dispenser. all test at conducted by a local pool store which in my view has done well in helping with pool water issues. values are obtained by sampling the pool water into a test cylinder and read via device. phosphates are tested by a dip stick. looking for direction.
chem geek
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Postby chem geek » Fri 22 Jun, 2007 22:35

First of all, you should get your own quality test kit, the Taylor K-2006 (from here or here or the even better equivalent kit here), and do the tests yourself. Second, unless you consistently maintained an absolute minimum Free Chlorine (FC) level of 5 ppm FC (6 ppm FC if the pH were 7.5), then you are likely fighting a nascent algae bloom that is consuming your chlorine. A CYA level of 85 is high and requires a higher FC to keep away algae. The normal target (at a pH of 7.5 and CYA of 85) is an FC level of 9.5 ppm. Did your pool store tell you about that?

To shock algae at that high CYA level requires a very high level of chlorine. So high that it might be better to do a partial drain/refill (or continuous dilution) of your pool to get the CYA level down to something more reasonable in the 30-50 ppm range. With 40 ppm CYA, for example, the FC target is only 4.5 ppm with an absolute minimum of 3.0 ppm that is much easier to manage and if you ever do need to shock, you only need to use 16 ppm FC to do so. The rough rule is that at a pH of 7.5, the FC needs to be a minimum of 7.3% of the CYA level, the normal target FC is around 11.5% of the CYA level, and the shock level (for green algae) of FC is around 40% of the CYA level.

I'll bet you are using Trichlor tablets/pucks as your source of chlorine (you said you had an auto chlorine dispenser). For every 1 ppm FC you add with Trichlor, you are also adding 0.6 ppm CYA. I suspect you might have a cartridge or DE filter that doesn't get backwashed. With a sand filter and regular backwashing, you usually get more dilution, but with your larger 22,000 gallon pool perhaps that doesn't help anyway.

I'll bet the pool store didn't tell you anything about Trichlor adding to CYA levels, did they? Or if they did, then they probably said that the CYA level doesn't matter, at least not until it's 100. And if you look on multiple pool forums you will see how treating for phosphates is the latest rage -- and expensive to boot. It's not really the pool store's fault since most are just following what the manufacturers are telling them.

After you reach a certain CYA level in your pool, say 40 ppm, then you need to switch to another source of chlorine that does not have CYA in it such as bleach or chlorinating liquid. Even Cal-Hypo would be better, though that increases Calcium Hardness (CH). Every 1 ppm FC from Cal-Hypo also results in an increase of 0.7 ppm in CH, but that's far less of an increase in percentage terms (with a CH of around 300) than with CYA. Note that you CANNOT use Cal-Hypo in a dispenser that was used with Trichlor EVER (the two are completely incompatible and can cause a fire or explosion -- in the pool water they are fine, but cannot come in contact with each other in concentrated form).

The downside with these other forms of chlorine is that they need to be added every day unless you have a pool cover in which case you can add chlorine 2-3 times per week.

Your other option, after clearing your pool of nascent algae, is to use a weekly dose of PolyQuat 60 algaecide. You could then use Trichlor, plus the pH Up and/or Alkalinity Up products that are also required (since Trichlor is so acidic) and not worry as much about the CYA, at least for a while until it gets well over 100 ppm. Another option is to add 50 ppm Borates (from 20 Mule Team Borax plus acid) as an algaecide, though PolyQuat 60 is more effective (and more expensive since you add it weekly).

By the way, is your in-ground pool vinyl or plaster/gunite? If the latter, then you should also check your Calcium Hardness. A pH below 7.0 is damaging to metal in equipment so generally you want to avoid getting that low, at least for an extended period of time. 7.5 is a normal target pH. If you use a "pH Up" product, that increases both pH and TA. If you use 20 Mule Team Borax from the grocery store, that raises mostly pH and only half as much for TA (same with lye which is another option for raising pH). If you do end up switching away from Trichlor as your chlorine source, then you'll want to lower your TA level to reduce rising pH, but that's down the road.

Richard
spike

Low FC level

Postby spike » Sun 24 Jun, 2007 11:04

Thank you. I do have a Taylor 2005 kit and use only Taylor reagents. The CYA as test by the pool store is correct. I will lower the CYA level by dilution. I struggled with this same issue all last year. It came to a head when the ran out of chlorine in the dispenser while away and came home to a "can't see the bottom cloudy pool". Super chlorination took care of the problem.

Yes we are using Trichlor pucks on the dispenser. We also do have a DE filter system which has beed recharged roughly 3 times sinces we opened the pool a month. This is common since the pool did have green algae growth and was dirty from the winter when opened. The recent recharge of the filter occured about two weeks ago. I expect to stick Trichlor as an oixidizer.

To clear the algae, shock or allow the chlorine to dispense of the it?

Yes it is a vinyl lined pool and I will correct the ph. Thank you for the note.
Buggsw
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Postby Buggsw » Sun 24 Jun, 2007 12:53

Chlorine is used to shock the pool. You get the chlorine up to shock level by adding enough chlorine.
no.name please

chlorine not reading

Postby no.name please » Fri 29 Jun, 2007 21:32

If your PH is too high - the chlorine might not be showing up on your tester. Hope this helps
spike

low FC

Postby spike » Sun 01 Jul, 2007 20:46

CYA has dropped to 60-70 from 85. PH 7.2
Using liquid chlorine only. Presently shock daily at 20ppm for the past 4 days. Will continue work down the stabilizer. Reading FC 0-.5 ppm and TC 1.5-2.0 ppm as measured in the morning.
What level should you shock at 60-70 stabilizer level?
What level of chlorine should you add daily?
How does total or corrected alkalinity affect the ability to maintain a FC level?

The pool water is cyrstal clear.
Frustrated
chem geek
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Postby chem geek » Sun 01 Jul, 2007 21:14

Shock level for green algae is about 40% of the CYA level (for yellow/mustard algae it's 60% of the CYA level). However, make sure your DPD chlorine test isn't getting bleached out by diluting your pool water with tap water (or filtered or distilled water). I am surprised you've still got high chlorine demand even overnight with crystal clear water.
spike

no free chlorine

Postby spike » Mon 02 Jul, 2007 14:14

The sample is dipped directly from the pool so I do not expect any diluting of the sample. I've have shocked at 30% not 48% on a CYA of 80.
chem geek
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Postby chem geek » Mon 02 Jul, 2007 14:53

I'm sorry I didn't make myself clear. I meant that if your chlorine level is above 10 ppm, then the DPD chlorine test (the one where you add 5 drops and it turns red and you measure the intensity of red) can bleach out from the high chlorine levels making you think you have no chlorine when you actually do. The dilution I was referring to would be intentional where you mix, say, one part of pool water with three parts of distilled or filtered water and then do the DPD test and multiply the result by 4.
udontknowhodou

lots of money to fix it

Postby udontknowhodou » Wed 01 Aug, 2007 22:49

My problem was the same, only to find out that i had the musterd problem, a fine powder like form of alg. LOOK IT UP! It made me drain, raised a phosphate level up and down trying to fight it. SHOCK< SHOCK< SHOCK. the problem is when you get it you have to hit it hard. try using yellow out or yellow treat. then flock it twice and vacum to waste. Follow the directions for yellow out and hit it hard with shock and make sure you raise your ph to 8.4 befor doing the process of yellow out. I would even hit it a third time with in 2 monthes. keep flocing and vacum to waste each time! always check ph and chlorine levels. When you vacum to waste, and readd tap water, the ph goes down. The ph, low or no phosphates, and chlorine are very important factors in killing the mess in a musterd infested pool. hope it helps.
car0407

Postby car0407 » Wed 22 Aug, 2007 23:25

this is my 2nd year that i haven't had a chlorine reading in my 21ft round above ground pool. my water is also crstal clear. whats the big deal if i don't get a reading? the water is clear. why not just go on with no chlorine reading?
xbombero
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Chlorine level

Postby xbombero » Mon 19 Nov, 2007 17:24

When you start your test if there is a flash of color and then it goes clear the cl2 level is too high for the test kit.

Don
BlindSite
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Re: lots of money to fix it

Postby BlindSite » Wed 21 Nov, 2007 03:33

udontknowhodou wrote:My problem was the same, only to find out that i had the musterd problem, a fine powder like form of alg. LOOK IT UP! It made me drain, raised a phosphate level up and down trying to fight it. SHOCK< SHOCK< SHOCK. the problem is when you get it you have to hit it hard. try using yellow out or yellow treat. then flock it twice and vacum to waste. Follow the directions for yellow out and hit it hard with shock and make sure you raise your ph to 8.4 befor doing the process of yellow out. I would even hit it a third time with in 2 monthes. keep flocing and vacum to waste each time! always check ph and chlorine levels. When you vacum to waste, and readd tap water, the ph goes down. The ph, low or no phosphates, and chlorine are very important factors in killing the mess in a musterd infested pool. hope it helps.


You're better off throwing everything you use in the pool into the water and throwing in a copper algaecide with good benzochronium after lowering the pH to about 7.0ppm.
lehighguy

chlorine

Postby lehighguy » Tue 13 May, 2008 15:07

You also should be looking at you alklinity level. If you have no alklinlity level your pool water is eating through your chlorine to get alkinlinity. I had to put 50 lbs of alkilinity increase last year and my pool leveled itself out and I was back to my once a month chemical checks!!

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