Even Leslie's Pool Supply can't help me. All of my values are perfect (ph, CYA, alkaline, calcium) except Chlorine. The free and the total both read 0 despite shocking the pool only a couple of hours ago. No matter what I do, I can't seem to get a chlorine reading. I have tablets in both skimmer baskets and I have shocked with two different kinds. But there is absolutely no chlorine in there despite the water being perfectly clear. Any ideas?
Chlorine
- Thread starter skilrain
- Start date
Welcome to tfp, skilrain 
What test are you using to test for chlorine? If you haven't tried it yet, try testing with the OTO chlorine test...this is the one that is typically attached to the ph block...it is more fool proof then other tests in at least indicating the presence of chlorine.
How does your water look?
Also, please post the rest of your test results for us to be most efficient.
What test are you using to test for chlorine? If you haven't tried it yet, try testing with the OTO chlorine test...this is the one that is typically attached to the ph block...it is more fool proof then other tests in at least indicating the presence of chlorine.
How does your water look?
Also, please post the rest of your test results for us to be most efficient.
Welcome.
"Perfect" is an imprecise value. Especially if the pool store clerk pronounced your water as such. Spend a while reading these forums and you'll soon discover that 1) Pool Store testing is at best, doubtful, and 2) Pool stores are in business to sell treatments, not give away testing. Have they tried to push any phosphate removers, algaecides, or other snake oils on you yet?
I find it hard to believe that a pool that has been dosed with pucks and powders will have "perfect" CYA. Typically, CYA is too high, which means the chlorine level has to be much higher to be effective - far above the center of the color block scale most test kits have. What kind of test kit do you have? Anyway, if the chlorine isn't high enough, algae can get started. You may be holding it at bay, but not killing it off faster than it can reproduce, which uses up all your chlorine, which is why you can't get a reading. And one day soon you may notice the water looking cloudy, and shortly thereafter, green.
Have you done any reading in Pool School?
"Perfect" is an imprecise value. Especially if the pool store clerk pronounced your water as such. Spend a while reading these forums and you'll soon discover that 1) Pool Store testing is at best, doubtful, and 2) Pool stores are in business to sell treatments, not give away testing. Have they tried to push any phosphate removers, algaecides, or other snake oils on you yet?
I find it hard to believe that a pool that has been dosed with pucks and powders will have "perfect" CYA. Typically, CYA is too high, which means the chlorine level has to be much higher to be effective - far above the center of the color block scale most test kits have. What kind of test kit do you have? Anyway, if the chlorine isn't high enough, algae can get started. You may be holding it at bay, but not killing it off faster than it can reproduce, which uses up all your chlorine, which is why you can't get a reading. And one day soon you may notice the water looking cloudy, and shortly thereafter, green.
Have you done any reading in Pool School?
I have a 19,000 gallon liner pool. I added 3 lbs of Power Plus Shock. Leslie's tested the water after I tested it because I didn't understand the Chlorine being zero. I have the side-by-side kind of tester. I cannot test for CYA. Leslie's did not try to sell me anything. They were just as confused as I am. They suggested that perhaps I have nitrates in the pool causing the chlorine to get used up and that maybe if I shocked it until the Chlorine read, I might have luck.
The pool was never shut down over the winter. We just bought the house 2 months ago. The water has been crystal clear the entire time. I have tried shocking it 3 times and have had chlorine tabs in the skimmers the entire time. I have never gotten a chlorine reading. In our last home, we had a pool for the past decade and had no issues at all except an occasional algae bloom when the water got up to 95 or so.
It all boils down to you're going to have to have a good test kit of your own. However take 2 large jugs of bleach and pour them into the pool then wait 30 mins and test the chlorine with your tester. Don't worry much about the value just if it turns some shade of yellow. Post back what you find.
I poured 2 jugs of bleach into the pool and measured the chlorine after 45 minutes. It reads 5.
With the kit you have we don't know if you have fc or CC's you should get a good test kit and take control of your pool.
My kit is a DPD with all the necessary ability to test chlorine levels. So I don't think it's the test kit's problem, but thanks anyway. I have run a perfectly good pool for 10 years without this issue ever coming up. I was just looking for some outside advice from folks who may have come across this before. I certainly didn't need someone to tell me to "take control of my pool". So thanks anyway. I'm sure I will figure it all out by myself, despite the pea brain you seem to think I have.
We HAVE come across this before, and it's usually astronomical CYA or things broke down into Ammonia over the winter, which requires a lot of chlorine to get rid of it.skilrain said:
Some test numbers would help narrow it down.
Buh-bye
We are just here to help, so bear with us...we don't have all the details of your pool that you do.
So you have the DPD test kit, what is your CC level?
Be aware the that the DPD test kit can only test up to 5 ppm FC (or 10 ppm FC in some test kits). Also, the DPD test can sometimes indicate 0 FC when the FC is quite high, which is why I asked if you had an OTO chlorine test, since that test is more bulletproof and will indicate the presence of chlorine even at high FC levels (though it will not give an accurate number at high chlorine levels).
Let us know if you want more help
So you have the DPD test kit, what is your CC level?
Be aware the that the DPD test kit can only test up to 5 ppm FC (or 10 ppm FC in some test kits). Also, the DPD test can sometimes indicate 0 FC when the FC is quite high, which is why I asked if you had an OTO chlorine test, since that test is more bulletproof and will indicate the presence of chlorine even at high FC levels (though it will not give an accurate number at high chlorine levels).
Let us know if you want more help
FC is now .5 while CC is at 1. The sun has been down for quite some time and the FC has decreased by too much already for the OCLT, so I will shock again. My CYA test kit should arrive any day now so I can check for that. The pool store said it was in range, but they didn't know my pool gets full sun all day. Thank you for the help.
It is great that you are getting that test kit, pool stores get cya more wrong than right and knowing your cya level is very important, especially for you now since you need to do the shocking process.skilrain said:
In addition getting the FAS-DPD chlorine test is also an important test to have. It can measure all the way up to 50 ppm FC unlike the the DPD test you have that can only go up to 5 ppm (10 for a few kits).
We would also recommend getting TA and CH tests since at some point you will need those results too.
skilrain said:
Welcome to TFP. With CC at 1ppm, it time to go through a shock process. Notice we use the word process as shocking your pool is a procedure not a product. Once you get a good read on your CYA level you will be able to determine your shock FC level.
Below are some quick links to pool school articles that should help and as you go through the process, please feel free to ask any questions you may have
pool-school/shocking_your_pool
pool-school/overnight_fc_test
Also, as you may have noticed..we really like to see test results, as it helps us guide you vs guessing at what the problem may be, below is a handy article we prefer all new members to understand. We are here to help.
pool-school/read_before_you_post