Actually when I got my initial CYA readings (45 and then 40) I had almost no FC (it was really hard to even get the reagent to turn even light pink and a single drop took me back to clear). From what I've read in the forums, having an CYA as high as it appears to be now would take a HUGE amount of bleach to reach my FC target. Plus as long as it remained elevated, won't I need to use much more chlorine to maintain proper levels?
Testing FC before and during slamming
- Thread starter ictshocker
- Start date
You can also get a 50ppm CYA standard solution (from TFTestKits.net) and use that to calibrate your test procedure
How is this different than the CYA testing I am using as part of my TAYLOR TECHNOLOGIES INC K-2006 test kit (testing using the .5 method)?
How is this different than the CYA testing I am using as part of my TAYLOR TECHNOLOGIES INC K-2006 test kit (testing using the .5 method)?
If you have a gram scale around the house you can just dissolve 2 grams into 5 gallons of water and see if you read 100 ppm CYA on your test. It's actually 105.7 ppm, but the test isn't that exact.
The pH buffering to lower pH in the CYA test is so that the melamine cyanurate is less soluble, specifically because it converts cyanurate ion to cyanuric acid that then precipitates with the melamine.
A high FC, on the other hand, can have most of the chlorine bound to the CYA and that can interfere with that combination from forming melamine cyanurate (details in this post). So I would NOT say that high FC does not affect the CYA test -- it might, though it would result in a lower than expected CYA reading, not higher. So if you want to test CYA at higher than normal FC levels (say, 10 ppm FC or higher) you could use sodium thiosulfate solution (R-0007) or hydrogen peroxide to dechlorinate the sample first. We normally have people test CYA at normal FC levels before a SLAM so this issue usually does not come up.
All this discussion should again underscore why you adjust chemistry before a SLAM. Once done, the only focus should be FC MAINTENANCE.
So I will take this that if my cya reading on two different tests prior to slam was 45 and then 40 after removing and adding water, I should not worry about tests I did after starting slam that indicated much higher cya. Guess I should have just not run the test "for fun" after the slam had begun....
I would ignore the CYA tests during the SLAM though we don't have an explanation for why its registering higher (if anything it should have been reading lower). After the SLAM you can test it again and see where it's at for confirmation.