Why did CYA Go Up.

[George Whitzel]

I had green algae and used the SLAm method to delete. I only added liquid chlorine from Wallmart the whole time. Somehow during the process my CYA readings raised from 60 to 80. As my algae problem just ended i still have an FC of 24 and CC of 0.5 or less. The FC is still to high to measure PH. Wondering what caused my CYA to rise?

 

[Texas Splash]

Wondering what caused my CYA to rise?

Only two reason really:
- Testing error/variance
- A stabilized product was added.

Since you used Walmart's LC for the SLAM, and if nothing else was used, I suspect it was simply a testing variance of some sort - ether the first test, the 2nd, or slightly both. Fairly easy to do really since the CYA test can be so tricky.

 

[George Whitzel]

I agree with your comment on the test being tricky especially trying to determine when the black dot totally disappears. Is there a recommended procedure for doing that?

 

[Texas Splash]

This is my go-to tip when doing the CYA:

CYA Testing:
Proper lighting is critical for the CYA test, so you want to test for CYA outside on a bright sunny day. Taylor recommends standing outside with your back to the sun and the view tube in the shade of your body. Use the mixing bottle to combine/gently mix the required amounts of pool water and R-0013 reagent, let sit for 30 seconds, then gently mix again. Then, while holding the skinny tube with the black dot at waist level, begin squirting the mixed solution into the skinny tube. Watch the black dot until it completely disappears. If it helps, pour a little, look away, then look back and pour some more. Once it disappears, record the CYA reading. After the first test, you can pour the mixed solution from the skinny view tube back to the mixing bottle, shake, and do the same test a second, third, or fourth time to instill consistency in your technique, become more comfortable with the testing, and validate the CYA reading. If you are still questioning your own results, have a friend or two do the same test 2-3 times. Share your results only after everyone is done to see if you came up with the same average results.

 

[George Whitzel]

Thanks I start using this method.