Chlorine test

[Nate1975]

I have a Taylor K2006 and K1000. The 1000 only tests for total chlorine. All I ever read on here is people talking about FC. When do I need to check for TC? What is the difference in the two?


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[JVTrain]

The FAS-DPD test uses the DPD powder and scoop to test for FC. This is a titration test where you add the powder to get a pink/red color and add R-0871 drops until it turns clear. This first number gives you the free chlorine (FC) level. You add the R-0003 reagent to turn the solution back to pink (if there is any CC) and then drop wise add R-0871 again until it's clear. The second titration give you the combined chlorine (CC).

The K-1000 test only gives you the total chlorine (TC) which is the sum of FC and CC.

FC + CC = TC

 

[Nate1975]

So if I am getting no reading on the 1000 test then I have no FC or CC.


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[JVTrain]

So if I am getting no reading on the 1000 test then I have no FC or CC.


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Exactly! Time to get some bleach in the pool!

 

[Nate1975]

Tested CYA and got a reading between 60-70...so I rounded to 70. Pool math said I would need just over 1 jug of bleach to get to FC 7. I went ahead and added 2 full jugs as we had lots of kids swimming today. I went out 45 min after adding bleach and am getting a reading of only 2 FC and 3.5 CC. Water is clear just not holding chlorine. Is my CYA the problem or?? Not sure what to make of that.


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[jblizzle]

When did you add CYA to the pool? Was it zero?

Having a CC that high is unusual and not good. So, you need to follow the ShockLevelAndMAINTAIN Process. Try to test every 30-60 minutes to start until the FC starts to hold.

 

[Nate1975]

I am transitioning from tri chlor and di chlor to bleach. Should I drain some water to start the process with a good cya level?


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[jblizzle]

It would not hurt to replace half the water ... still will need to SLAM though.

 

[Nate1975]

When draining...do I just drain a little then keep testing until my cya is in the normal range? Then refill and begin SLAM?


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[jblizzle]

No. Your CYA will drop by the same % as the amount of water you drain.
If you drain 50% and then test that water, the CYA will still be what you started with. Then you refill and it dilutes it to be 50% of what you started with.

Your CYA is really not that high and perfectly manageable.

 

[Nate1975]

So if I don't drain it will just take more bleach to reach the target levels? I am curious why the amount of bleach pool math figured didn't raise the FC to the level it calculated? I tested my cya twice and it was in between 60-70 both times. Any other reasons?


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[jblizzle]

Because something is in your water consuming the FC as fast as you add it ... thus the high CC level.
I suspect it could be an ammonia issue which is why I asked if you had recently added all that CYA.
But, I am not sure ... end result is you need to keep adding bleach until the CC drops and the FC holds and then follow the SLAM process.

 

[chem geek]

Tested CYA and got a reading between 60-70...so I rounded to 70. Pool math said I would need just over 1 jug of bleach to get to FC 7. I went ahead and added 2 full jugs as we had lots of kids swimming today. I went out 45 min after adding bleach and am getting a reading of only 2 FC and 3.5 CC. Water is clear just not holding chlorine. Is my CYA the problem or?? Not sure what to make of that.

Just to make sure, you used a 10 ml sample size and it took 4 drops of FAS R-0871 drops during the first part of the test for FC and then after adding 5 drops of R-0003 it took 7 drops of R-0871, is that correct? If so, then indeed the 7 ppm FC you added looks like it may have combined with some ammonia or something else fairly reactive to form the CC and deplete some of the FC beyond that possibly starting to get rid of the CC. The good news is that you had at least some FC which means it hopefully won't take a lot of chlorine to recover from this. You could SLAM to make the CC go away faster. If it's from ammonia, then 90% of it should go away in 4 hours or so, but you'll need to add more chlorine so add some more now and then see where you end up. If the CC is still there by tomorrow morning, I'd SLAM the pool.

 

[Nate1975]

Yes that is correct. Is there a test for ammonia?


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[JVTrain]

Yes that is correct. Is there a test for ammonia?


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You can pick up an ammonia test at most pet stores with fish supplies. Used to test aquarium water.

# Sent from mobile device. Beware of brevity and spelling errors!

 

[Nate1975]

If it's an ammonia problem, then I assume my CYA reading would be down the next time I check it? What is the solution if there is ammonia?

 

[jblizzle]

More chlorine. Test and add every 30-60 minutes.

 

[Nate1975]

Am I wanting to maintain chlorine levels at shock level or just normal FC range?

 

[jblizzle]

Shock level if you can get it that high.