Newbie ... Chlorine Lock?

Aug 14, 2008
25
I've been testing my chlorine for the past couple of weeks and it keeps remaining high. I took a water sample to the local pool store and the cya is 85 with TC & FC at 10 and PH at 7.3. (30,000 gallon pool w/DE filter) Is there any way to lower the cya without replacing water in the pool? We were using the chlorine pucks - should I just be using regular chlorine bleach? Should I shock the pool? I'm worried the chlorine isn't working.

The pool store also said the alkalinity was 89, but the adjusted alkalinity was 63. What is adjusted alkalinity? They said I should add 35 pounds of baking soda - this seems like an awful lot! Any thoughts? Thanks so much!
 
Stop using the pucks. It will add CYA to your pool. Just use liquid bleach you can get at Wal-Mart. You can not use sented bleach it has to be pure bleach.

If you dont have a reliable testing source for your water, to test yourself you should purchase one ASAP. There is a link in my signature for a great test kit most of our members use here that is sold by one of our members OR I suggest the Taylor K2006 test kit.

The only way to lower CYA is by water replacement. I am not sure what they mean by adjusted TA, but someone who does will chime in and let you know more about it. If your TA is either 89 or 63 it is low. You dont mention what your pool water looks like. Is it clear, cloudy etc?

It would be helpful to us if you could list in your pool type and equipment in your signature so we can answer you questions better. Go to control panel.
 
You don't need to think about adjusted TA. We always use TA readings directly from the test here.

Why are you worried about chlorine lock? Do you have algae? With a CYA of 85, as long as FC remains around 10 you should be fine. Longer term it would be good to lower CYA a little, but CYA will come down on it's own slowly, which is probably good enough.
 
Notice how Jason has a link to the pool school in his signature, and also a link to the pool calculator. If you click on the link to the pool school, one of the topics is a chlorine / CYA chart. If you click on the link to the pool calculator, and in the calculator you put your level of 85 in CYA, down lower on the pool calculator, you can find your suggested level of FC. Both sources say that for 85, your lowest limit is 7. 10, like Jason said, is a good target level. It's plenty high enough to work!

At this point in the season, it's probably better just to run with the higher CYA and keep your chlorine high, than to drain the water to get your CYA down, unless you live somewhere where you have a very long season and still will be swimming until late October or so!
 
Thanks so much to everyone. We just moved into a house with a pool and this is all very overwhelming for me. My husband also just left for Iraq so I'm trying to learn this stuff by myself and in the most cost effective way. (just a little stressed) I don't notice any cloudiness in the pool water - it's very clear and nothing appears to be growing. I was just getting concerned about the constant high chlorine level and started reading about CYA. I definitely need to get one of the test kits you guys recommend. If I stop using the pucks, how do I know how much liquid bleach to use in the pool? Should I still shock the pool? Do you think I should add all the baking soda the pool store recommended? We have a 30,000 gallon in ground plaster pool with a waterfall, a DE filter and the ray vac thingy. Thanks again to everyone!
 
The pool calculator will help you know how much bleach to use in the pool. To give you an idea, 1 gallon of 6% chlorine bleach raises the chlorine level of a 10,000 gallon pool by 6ppm. And to give you another idea of how easy this really is, once you get everything started; my hubby didn't want anything to do with pool care. In the evening, I go out with my test kit, a gallon of 10% bleach, and a measuring cup. I test my chlorine, and as long as I don't skip a day, put 1 cup of bleach in the pool (mine's smaller than yours; 9400 gallon above ground.) If I skip a day, I have to put a little more. It's that simple, though, and takes longer to walk out to the pool than to do the daily chlorine / ph test and add the cup or so of chlorine. The TF100 comes with a daily OTO / Ph test kit in a little blue box, BTW, that has a cute little chart in it saying how much chlorine to add per gallons of pool. That chart is very handy.
 
Hi there, just wanted to chime in. Read the article in pool school about shocking your pool, it's not something you'll need to do regularly, only in certain situations. I was just commenting on another thread that I have only had to shock 3 times in 2 years. 2 vacations, and then last fall when I closed my pool.

I would not add the baking Soda, if your TA is almost 90 and you stated you have a waterfall feature. The waterfall is a source of aeration for your water. If you put in the baking soda, it will raise your TA and your PH. When your TA is above 100 and you have an aeration feature like a waterfall, people tend to see their PH creep up and get too high, also called PH Rise. So I would just wait, now that you are no longer using the pucks and will be using bleach those numbers should be fine, you may in time even find you have the PH rise because of your waterfall. You want your PH below 7.8, 7.6 is a great target. Also, you don't mention how old the pool is; new plaster tends to see the PH creeping up, so now that you are using bleach you may also want to pick up some Muratic Acid from the pool or hardware store. If you see your PH go above 7.8 you'll need to lower it with the Muratic Acid.

Make sure you keep enough bleach in there to keep your FC at the recommended target for your CYA - see the chart. You don't want it to go below the minimum or you will likely get algae.

You'll be fine, I know it's overwhelming but overtime it will get easier. Just keep reading here, read everything....it will begin to sink in and you'll feel less overwhelmed. I do recommend you read the article in pool school that compares the test kits. I think you should get the good kit asap, a pool that sounds that nice - the test kit is the best investment in your pool you could make. :)
 

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