CYA test inconsistency

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Thormus

Thormus

Bronze Supporter
Jul 8, 2019
78
Meridian/ID
Hi,
I'm fairly new to this whole TFP thing. I ran the CYA test 3 times now. first times it was close to 80 but today it showed up at 95. I have stopped using all pucks / trichlor and my chlorinator is off since my first test. I may still have pucks in there and maybe it has a leak? Or have I been performing the test wrong and my real CYA is 95? I have been floating a .5 CC for two weeks even at recommended chlorine levels. Any insights?
 
Take the pucks out in case the chlorinator has a leak.

The CYA test really can’t be read between the lines. Round up. You need to be careful because your CYA is getting high enough to make the FC levels tough to manage. Let it come down or exchange out a ton of water in a pool that size.
 
IceShadow said:
Take the pucks out in case the chlorinator has a leak.

The CYA test really can’t be read between the lines. Round up. You need to be careful because your CYA is getting high enough to make the FC levels tough to manage. Let it come down or exchange out a ton of water in a pool that size.
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I will dump the pucks out of theyre in there.
 
The test is only +/- 10ppm, so those 2 results are within the accuracy of each other. Plus lighting has a significant impact on the test results, so that could influence the result.
 
jblizzle said:
The test is only +/- 10ppm, so those 2 results are within the accuracy of each other. Plus lighting has a significant impact on the test results, so that could influence the result.
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+1
My reading will change by at least 10 going from the recommended place of outdoors in full sun with back to sun as apposed to in my well lite garage.

If you purchase and try there 'standard solution' it will greatly increase your confidence level of the test.
 
Welcome to TFP! Our experts will need a little more information. Can you please answer the following:
  • Now that you've gotten the tablets out how are you chlorinating?
  • What does your pool look like? Crystal clear, cloudy, discolored? A photo would be very helpful.
  • Please post a set of TF 100 results.
  • When you say you have been in range for your FC what range has it been?
Your CYA is very high, and the test is logarithmic so you always round up. Your result would be 100. A cc of .5 can indicate you have insufficient FC to fully oxidize the organic contaminants and/or CYA is interfering also. This can happen as a transient but normal condition or it can be you are on your way to a problem Hard to really tell what's going on without a full set of test results and more information.

Chris
 
setsailsoon said:
Welcome to TFP! Our experts will need a little more information. Can you please answer the following:
  • Now that you've gotten the tablets out how are you chlorinating?
  • What does your pool look like? Crystal clear, cloudy, discolored? A photo would be very helpful.
  • Please post a set of TF 100 results.
  • When you say you have been in range for your FC what range has it been?
Your CYA is very high, and the test is logarithmic so you always round up. Your result would be 100. A cc of .5 can indicate you have insufficient FC to fully oxidize the organic contaminants and/or CYA is interfering also. This can happen as a transient but normal condition or it can be you are on your way to a problem Hard to really tell what's going on without a full set of test results and more information.

Chris
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Only liquid chlorine 10% from Walmart.
Water is crystal clear
I will post a pic once I get the sun cover off today.
When I say I’m range I meant for 80 CYA.
 
Your FC is too low based on your Poolmath logs. With a non-SWCG pool, your minimum FC should not go below 7.5% of your CYA. At a CYA of 95, you need 8 ppm FC as your minimum.
 
Best thing to do in my opinion is to get the 50 ppm CYA standard solution from TFT. Do the test at high noon,Back to sun, etc with the 50 standard. See what it looks like in that position. Immediately after do the pool water test in SAME position and measure. You should have a very good idea now what to look for after doing the standard solution test. I do this frequently.
 

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Bvacchiano said:
Best thing to do in my opinion is to get the 50 ppm CYA standard solution from TFT. Do the test at high noon,Back to sun, etc with the 50 standard. See what it looks like in that position. Immediately after do the pool water test in SAME position and measure. You should have a very good idea now what to look for after doing the standard solution test. I do this frequently.
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I’m using the TF-100 test kit. Isn’t that the same CYA test?
 
Yes, but he is saying to get the 50 ppm CYA solution that they offer and test that. You know it will be 50 ppm, and you can see what that looks like. It helps calibrate your eyes to the test so to speak.
 
I removed my chlorinator from the equation. It was still had pucks and a little bit of water. I think my CYA is at 95-100 now. :( I re-did the CYA test at noon with my back to the sun outside.
 
Last edited:
Thormus said:
It was still had pucks and a little bit of water
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Sorry, not sure what you mean by this. Can you please explain? Remember, CYA test is logarithmic, so a reading of 95 on the tube is rounded up to 100. I bet your technique is better than you think and your CYA is high.
 
setsailsoon said:
Sorry, not sure what you mean by this. Can you please explain? Remember, CYA test is logarithmic, so a reading of 95 on the tube is rounded up to 100. I bet your technique is better than you think and your CYA is high.
Click to expand...
So when I found this forum and pool school I stopped using trichlor from a chlorinator. I turned it to off. My initial readings from my tf-100 kit were at 80 for CYA. I had been using liquid chlorine since then. However it seems as though somehow my CYA levels have risen. Today I disconnected my chlorinator because it had a few undissolved pucks in it. Just in case it was letting some water through.
 

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