help figuring out chlorine in pool

Oct 30, 2011
22
i am new to the pool world only have my pool for about 3 months now. it is a sport pool that is 14X28 it goes to 6 foot in the middle. the pool levels are: ph 6.3, TA is around 140 and chlorine 1 or less and free chlorine is 1 or less. i have an auto pilot nan and it has been running at 100% for a day or so. I just checked it and the chlorine levels are not improving. we had a bunch of rain almost all last week and the salt lever drooped to 2100. i added 2 bags of salt and the swg now says it is 3600 ppm. i have added Clorox to boost the fc, and a box of 20 mule borax to raise the ph. the chlorine has not raised and neither has the ph. what am i doing wrong? thanks..
 
Your PH is pretty low, you should get that up to 7.5 or so. How are you getting your numbers? What is the CYA and CC levels? Is the pool in a really warm location with lots of sun?

No CYA will make the chlorine burn off quickly especially if you're in a warm area with lots of sun. A CC level higher than .5 will also eat the chlorine. Keep adding bleach to maintain a minimum of 3ppm until it is known what is going wrong here.
 
How are you testing?

It is possible your PH is lower the 6.3 - is that where your test bottoms out? Try raising it again and see if you register the change.

The chlorine is either - burning off in the sunlight quickly (no CYA) or being consumed by organics in the pool. Can you test for CYA?
 
i test with strips and the liquid you buy at walmart with the red drop and yellow drops. how much borax does it take to raise the ph. the ph is low because i made a mistake. i though i poured a bottle of liquid shock in the pool but i ended up pouring in a bottle of meratic acid. i also shoched it this past saturday, i added two bags of shock to it is that not enough. also i have been adding stabilizer to the skimmer, that is cya right? think i may have added to much. all i see are 5 and 6 way testers where can you get one that test cya and cc?
 
Check out PoolCalculator.com You can use that to Calc how much chems to add for certain situations. We can help you calc it too - but give it a try first.

If you are looking for a good test kit - tftestkits.net is where a lot of us get our gear. Their TF-100 is good value, will last you many years and has the FAS-DPD chlorine test that most kits do not.

I get your pool Gallons somewhere around 11,000 to 13,500 gallons. Depends on how much is shallow end, etc.

1) PH - hard to say how much borax becuase we dont know how far below 6.5 you are. Just target raising 6.3 to 7.5 on the pool calculator and start there. I get 380oz of Borax

2) What is the powdered shock you are using? What Chemical - it'll say Calcium Hypo or Dichlor most likely. Either way - stop adding stabilizer. You dont want too much CYA in the water as it will make your chlorine less effective.

3) Chlorine is something that is continuously used up by the pool (by killing bacteria and algae, or sunlight). So if you are adding chlorine but then can't test for it - it is going somewhere. The short answer is you need to add more chlorine until you've killed off all of the contaminants in the water. There are articles in Pool School on properly shocking the pool.

As to your SWG - it's possible that it is working fine, but cannot keep up with the chlorine needs of the pool because there are things growing in the pool. After completing the shock process you'll be able to better tell if the SWG is producing sufficient chlorine for the pool.
 
Test strips are not very accurate. You'd have to run the numbers through the pool calculator to figure out what to add to get the ph up. The drops are ok for a daily quick test but you'll need a real test kit to test cya and CC, one like the TF100. This link shows the differences: pool-school/pool_test_kit_comparison. Hit the pool school link to find out more. My concern is your CYA level (stabilizer) may be getting high seeing you are adding it plus adding powdered shock which also has it. Liquid chlorine is your best bet until you get your levels on here.
 
cool i will buy me one of these kits, until then how should i proceed , should i go get come liquid shock and keep shocking it? if the cya is high how do you lower it. googling the net said you have to drain the pool, it that right
 
Unfortunately partially draining the pool is the only way to lower the CYA.

BUT - we dont know what any of those levels are at the moment - so there is really no need to drain anything. I would correct the PH as soon as possible because low PH can be hard on everything.

I would start with Pool School. It sounds like you've read through it - but go through it again until all those little abbreviations begin to make sense.
 
You say you've had the pool for 3 months, does that mean it's new or just new to you? If it was filled 3 months ago then the CYA shouldn't be too high yet. If the water looks good you could put enough bleach (chlorine) in to maintain 4 or 5 ppm until your kit arrives. Unless you have low CYA, the best bet is to only use bleach even to shock.
 
i took a water sample to the pool store today. i guess i really need the new testing kit bad because what my kit said that what their computer test said was completely different. my swg says my salt ppm is 3500 they computer read out sait said it was 2100. my said ph was 6.5 theirs says it is 7.8. my said TA is 120 theirs said it was 180. also they told me the cya is low at 8. also, it rained cats and dog here today and my wife called me at work and told me the pool was green. got home and it sure enough it is green. i was clear yesterday. also i have a tree branch right over the pool, is that causing any problems. the pool store told me to add three bags of turbo shock to it and a bottle of algicide 60. lastly the pool is new filled it up in march.. thanks for any info you can give.
 

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Do yourself a favor and order one of the recommended kits ... obviously the pool store seems questionable at the least.

Odds are the CYA is low so not draining will be required. Forget the Turbo Shock and the algaecide (never needed). When you get your kit you will need to check the pH, add CYA up to about 30ppm and start the shock process.

Until then, you could add some bleach everyday to try to hold the algae at bay.
 
Those computer read outs are really unreliable. I wouldn't trust any of it.

The only thing that is going on in your pool is the algae is growing faster than the chlorine can kill it. So you add a certain amount of chlorine - it kills a certain amount of algae and gets used up. Then the algae is allowed to grow - and you are back to square one.

The shock procedures in pool school are designed to avoid these kinds of issues - but without accurate test results it's tough to give good advice.

As to your PH mystery - are you using strips or a drop test? If it's a drop test I'd trust it over the store.
 
If your CYA is really 8 then you can use powdered chlorine to shock because it will also raise your CYA at the same time. This is what I did this spring until I got my CYA up and my SWG going. Two birds with one stone. Seeing the pool water is new your CYA is probably low. The pool calculator will tell you what is needed to shock it. No algaecide needed. As for salt level, ignore them and trust your SWG. You can buy a separate salt test kit if you want. Strips are pretty accurate for salt as long as they are not old.
 
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