"Chlorine Block"

JEM31

Well-known member
Jul 13, 2020
58
NJ
We opened our pool June 18th. It was cloudy but green. We shocked it. The next day we took the water to get tested... actually to 3 different places. They all pretty much said the same thing...chlorine block. We still hsve nnnot been able to break it. We've put in about 18lbs. of Shox, super chlorinated it twice with 5 gallons of liquid shock but still no good, although the difference between the free chlorine and total chlorine have gotten closer. We've had a lot of rain so a lot of fresh water got in the pool. They said to put 8 to 10 gallons of liquid shock in. Im trying not to do that bez I use the pool everyday for exercise therspy. The ph is 7.8, cyuranic acid is 5 but they said to leave it alone right now, pool is cloudy but can see the bottom. I vacuumed it last nught and put in algaecide and clsrifier so today its more cloudy. I think maybe I should change the cartridge becsuse maybe all the algae is tying up the chlorine. It does not have any order at all. Thank you for any help you can offer. The pool stores use a computer to test the water and I don't think the young kids that work there know much about water chemistry.
 
Welcome to the forum!

You need to follow the SLAM Process. To do that, you need a proper test kit. I suggest the TF100. A proper test kit is needed to get the accurate water chemistry results needed to follow the TFP protocols.

While you are waiting on your test kit, add 5 ppm FC worth of liquid chlorine / plain bleach to your pool each evening with the pump running. This will replenish the FC lost each day to the sun and also inhibit any algae in the water from growing further.
I suggest you read ABC's of Pool Water Chemistry.
 
Thank you. Where can I get the test kit? The hyperlink wont work. How do I calculate 5ppm? Pool is about 15,000 gallons. We have an automatic chlorinator with tableys but they said not to use them because it would put more chlorine in the pool and increase the block.
 
Seriously... get the test kit.. and leave the pool store in the dust... Download the pool math app.. and follow it... if you need help.. the community here will help you far more than any pool store.. I started following this site last year when I had my first problem... bought the TF-100 test followed directions ... and never looked back. you will too
 
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These are the levels from yesterday's test at the pool store, by computer. FC 0.5 ppm, TC 1.72 ppm, CC 1.22 ppm, ph 7.8, hardness 7.8, alkalinity 101 ppm, cyanuric acid 5 ppm, copper 0 ppm, iron 0.1 ppm, phosphate 162 ppb. We did put in a chlorine tablet yesterday just to help kill the algae.
I don't know if this has anything to fo with it but last year when we opened our pool it was a swamp...I mean a slimy swamp. Couldn't see the bottom. We shocked it and we shocked it and vacuumed to get out all the algae, etc and cleaned the cartridge so many times. After about 3 weeks we finally got it clear. Not crystal but clear. We still have that same cartridge in this year. We clean it evey could of days because we vacuum every couple of days to get out as much algae. Could the cartridge be ineffective? Maybe all the old algae etc. is harboring in there? We ordered a new cartridge but it's on backorder due to the shutdown. Should we change the cartridge? Maybe it will filter better?
 
The cartridge is not ineffective, it is working really well. You have algae in the pool water.
Clean the filter when your pressure rises by 25% over the clean filter pressure.

Get your test kit. Follow the SLAM Process
 
With the SLAM process can you still go swimming?
You can safely swim in a pool as long as the FC is above the minimum and at or below SLAM level based on your CYA. You must also be able to see the bottom of the pool in the deep end of the pool.
 

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Ok. So I hit my test kit and I did the test. The daily test results were 7.5 ph and .5 chlorine. The results for the extended tests are Fc 0.5, CC 0.5, TC 1.0, Alk 110 and I emptied the entire bottle of solution into the test tube and was still able to see the dot. I know with the pool store results it has consistently tested at 5. We've been adding a gallon of liquid shock at night because I couldn't find 10% bleach and we put chlorine tablets in the auto chlorinator. It's cloudy but I can see the bottom but there is also algae in the bottom. I vacuumed again yesterday and we cleaned the b filter. Ugh!! Is this ever going to get better or should I just get rid of the pool lol. (Rhetorical question lol).
 
How many tablets have you added? Each one has added 2.2 ppm CYA to your water.

Count them up. Then add the balance needed of CYA dry granules (stabilizer, conditioner) to get to 30 ppm CYA. Add the granules to a sock and start them dissolving hanging in front of a return to the pool.

Once you have that started, Add liquid chlorine to reach 12 ppm FC. That is your SLAM level. Test FC and add liquid chlorine every couple hours to start. Maintain 12 ppm FC. No need to run any other tests while you are in the SLAM Process
 
We added 1 the day before yesterday and today my husband added 6 to the chlorinator, but they take awhile to dissolve.
So we're expecting a storm tomorrow so should I do that on Saturday. It's the start of a heat wave on Saturday so I'm afraid the pool will turn completely green.
Where is the least expensive to get shock and cya granuales?
Thank you.
 
7 times 2.2 is 15 ppm CYA. So add 15-20 ppm worth of dry CYA. NO more tablets. Let those you added dissolve.
Start now. Storms will not bother. Less sun will actually help.
Not sure where in NJ you are. There is a place called Ocean State Job Lots that carry pool products. Also Walmart, Home Depot, etc.
 

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