How long until I can test for CYA levels?

[famdog]

24' AG w/new water:

I've dissolved 3# of CYA in my skimmer in the last week (in an old tube sock) and my CYA levels are still too low to test for (below 30).

I added another 3# into the sock last nite.

Q: when the sock is empty, will the conditioner test be accurate, or do I have to wait longer than that?

thx.

[catnip]

How many gallons are in your pool? Based on the diameter you give, I suspect 3 lbs. of CYA is enough. BleachCalc say 12 ozs. will raise CYA by 10 ppm in a 10,000 gallon pool. And 30 ppm should be plenty in a non-SWCG setup. If you average depth is 4 feet, you have 13564 gallons. So, to get 300 ppm you would need 3 lbs. 4 ozs. of CYA.

I'd advise you to remove the sock with undissolved CYA immediately and wait a couple more days. Also, you might verify your measurement with another test kit. You should be seeing a definite cloudiness in the test solution by now. Also, be sure your pump is running to dissolve the CYA that may still be in your filter. And lastly, did you happen to backwash or clean your filter after you added the CYA last week? If so, you may have lost the CYA that was still lodged in the filter and not yet dissolved.

[famdog]

My pool is 14,600 gallons and the pump has been running 24 hours for 6 days straight w/o a backwashing.

According to this site: http://www.csgnetwork.com/poolchemcalc.html

I can add 6# of CYA to get the level to 50ppm

I'm just curious how long after the sock is empty do i have to wait for the reading to be accurate...

thx

[catnip]

CYA does not dissolve readily in water, so it can take a while to fully dissolve. How long depends on water temperature and water flow around the particles. But based on my own personal experience and others who have posted here, a week should be plenty.

With you CYA at 50 ppm (when it eventually gets there) you will need to keep you FC at between 3 and 6 ppm ALL the time to keep a good level of sanitizing chlorine. Here is a post that gives the specifics:
http://www.poolforum.com/pf2/showthread.php?t=365

[scsteven]

My pool person once told me that the pool water had to reach a certain temp (I think she said 75 degrees) before it's worth while to test for CYA. Has anyone else heard this?

[chem geek]

Many of the chemical tests should be done with the water closer to room temperature. They are designed to be measured at those temps (70-85). You can just let the water remain covered in its container sitting at room temperature until it warms up. Then do the test.

If the water is cold, then the CYA test will not form a precipitate as quickly in 30 seconds. If you let the water warm up first before doing the test, then it should be fine.

Richard