how to adjust total chlorine

Causes and cures for cloudy swimming pool water.
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pup55

how to adjust total chlorine

Postby pup55 » Sun 23 Aug, 2009 11:20

Can someone tell me how to lower or adjust my total chlorine and free chlorine? I keep having problems with algae growth in my pool this year. Could the total and the free chlorine being to high cause problems to my pool? My total chlorine is 10 and my free chlorine is 10 and a cannot seem to get it lower. I have an off line feeder and I keep adjusting it and they both stay at 10. Could this be the cause of the algae growth?


Me...
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How to adjust total chlorine

Postby Me... » Mon 24 Aug, 2009 10:13

Erosion Feeders are a great way to feed pucks but really not a great way to maintain stable chlorine readings. Try to use only 1 or 2 pucks and keep the valve at the higher end or the feed rate. Bigger pools might need 3 pucks but I doubt many need more than that.

When you fill the feeders right up all the pucks start to erode and even turning the dial down, you still have all the pucks dissolving. Makes it tough to keep an even, stable reading especially in smaller pools.
pup55

how to adjust total chlorine

Postby pup55 » Mon 24 Aug, 2009 16:42

Thanks I will try that. Is there a better way to add chlorine to my pool? It is an inground with about 28,000 gallons.
nocturnalsheep
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How to adjust total chlorine

Postby nocturnalsheep » Mon 24 Aug, 2009 17:57

A free chlorine level of 10 is nothing to worry about as long as no one is complaining of a chlorine smell, itchy eyes, or dry and irritated skin. To get rid of chlorine when is does get to high, a common product that is used is called sodium thiosulfate (or thiotrine). The dosage for this product is 1 oz. per 10,000 gallons of water to neutralize 1ppm of chlorine.

Chlorine won't be the cause of your algae growth. Chlorine is a sanitizer and thus actually kills algae. If it is just green or mustard algae, you probably should try using an algacide (make sure that it isn't just a preventative) in conjunction with a heavy dose of chlorine. This process essentially works as a 1-2 punch; the algacide weakens the chlorine and the chlorine wipes it out with one final blow. If you have a sand filter with a multiport valve, though, you would be better off physically removing the algae by floccing it and vacuuming it to waste. Killing an algae bloom only makes the next one stronger.

As far as a better way to add chlorine to your pool, a granular chlorine is the best way to keep the free chlorine at the necessary level because you can add as much as you need rather than relying on a slow steady addition (from the tablets). The problem with tablets is that they often times have a difficult time keeping up with the chlorine demand (if it gets to high). If this happens and your chlorine gets overwhelmed it combines with the organic material (swimmer wastes) and becomes what is called chloramines. Once this happens, until you get rid of the chloramines, any chlorine you add only makes the issue worse. A non-chlorine shock is the best and often least expensive way to get rid of chloramines.

For your pool (28,000 gal.), the chlorine dosage would be:

7oz. chlorine at 99% concentration (which would be a good sodium dichlor such as Bioguard's Super Soluble) would bring your free chlorine level up 1 point (ppm)

Let me know if you have any more questions!

-Danny
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How to adjust total chlorine

Postby chem geek » Tue 25 Aug, 2009 01:30

nocturnalsheep wrote:For your pool (28,000 gal.), the chlorine dosage would be:

7oz. chlorine at 99% concentration (which would be a good sodium dichlor such as Bioguard's Super Soluble) would bring your free chlorine level up 1 point (ppm)

Do NOT use Dichlor unless you intentionally want to increase the Cyanuric Acid (CYA) level in your pool. Higher CYA levels will make the chlorine less effective leading to algae growth unless you proportionately raise your FC target to keep the FC/CYA ratio constant or use a supplemental algaecide at extra cost. The following are chemical rules of fact independent of concentration of product and of pool size:

For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by 7 ppm.

Chlorinating liquid, bleach and lithium hypochlorite will not increase CYA nor CH, though lithium hypochlorite is very expensive. This is why chlorinating liquid or 6% unscented bleach are the most common chlorine choices used in pools managed with chlorine alone and no extra-cost algicide, clarifiers, phosphate removers, etc. However, the downside is that the chlorine must be added every day or two unless you use a pool cover and even then it needs to be added about twice a week (unless you don't mind large swings in chlorine concentration).
pup55

how to adjust total chlorine

Postby pup55 » Tue 25 Aug, 2009 15:40

Thanks guys for your input. So with the FC and the TC at 10 it should not cause any problems except for the skin eyes and so on. I am the only one that use's the pool and it doesn't seem to bother me. I will keep working on the pool till I get rid of the algae. Thanks for the help.
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how to adjust total chlorine

Postby chem geek » Tue 25 Aug, 2009 22:34

If you've got Cyanuric Acid (CYA aka stabilizer or conditioner) in the water, then this will significantly moderate chlorine's strength so even 10 ppm FC will not be irritating. For example, 10 ppm FC with 50 ppm CYA has the same amount of active chlorine (hypochlorous acid) as around 0.2 ppm FC with no CYA which is lower than in indoor pools. Normal shock levels would be an FC that is 40% of the CYA level and is equivalent to a pool with around 0.6 ppm FC with no CYA.
pup55

how to adjust total chlorine

Postby pup55 » Wed 26 Aug, 2009 16:43

I checked my pool when I got home from work and the algae is back.
With 2 different test strips.(I am buying a test kit this week)
TH 100
TC 10
FC 10
PH 6.2
TA 80/120
CA It is to low to read ?

I can now smell chlorine when I am in the pool. I am pretty sure I am having problems with the chlorine not sanitizing the pool. Also any time I add powdered chemical the pool turns cloudy right away and takes a good week to clear up. HELP!!!!!!!!!!!!!!
nocturnalsheep
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How to adjust total chlorine

Postby nocturnalsheep » Fri 28 Aug, 2009 13:29

Well the first thing you need to do is balance the water. Your pH is very low and thus the water is acidic. You will want to find an alkalinity level that holds your pH where it needs to be (ideal=7.4 to 7.6, acceptable=7.2 to 7.8). Bring it up little by little until you find your pH leveling off in that range.

You do want a certain amount of CYA in your water, that is why I was suggesting a dichlor. If I remember correctly, the industry says 30 to 50 ppm is ideal, but realistically you can go a bit higher than this and not have any issues. Dichlor is also more concentrated and thus will raise the chlorine with less of the chemical. Calcium Hypochlorite is probably the cheapest chlorine you will find and right now it would be alright for you to use it (because your calcium level is not high), but I would still recommend a dichlor for the time being because it is a good idea to have some CYA in your water to protect the chlorine from the sun.

Balance your water now, though. That is your priority for the time being. Acidic water is unsafe for swimmers and equipment.

-Danny

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avi

how to adjust my pool

Postby avi » Tue 29 Jul, 2014 04:19

hello
i just build a pool operated by salt and i am trying to adjust my pool
can someone help?
my reading is:
tc: 0
fc:0
ph:8.4
total alkalinity: 240

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