After drain how quicly should CYA drop?

[jhever]

I had my water tested at the pool store (my TF100 is on its way) and my CYA was at 150. I drained about 50-60% of my water and then refilled it over the weekend. It was done refilling Sunday morning and I ran my pump 24/7 to circulate the water. I took a sample to the pool store Monday night and they still tested my CYA at 150! What a downer after all my work draining for the first time. They tested it 2 times with two different types of test and still got 150.

Does it normally take a few days to show a change in CYA? I was hoping for SOME improvement!!

 

[ouachita]

It doesn't drop, it get dilluted. It should have come down immediately. You might consider ordering a test kit and doing it yourself.

 

[Isaac-1]

Your CYA may have been extremely high reading off the top of the test range, and may still be off the top of the test, I suggest you dilute it with tap water 50/50 and retest for CYA (there should never be CYA in tap water). The only other possibilty assuming the test was done right is you did not get the water to mix, if for example your pool water is warm and your fresh fill water was cold it would sink to the bottom, and if you circulated with only the skimmer running most of that fresh fill water could still be sitting on the bottom and not mixing with the warmer pool water.

 

[jhever]

Thanks everyone. I'll check to make sure my main drain valve is open to get better circulation. I'll test it myself when my test kit arrives.

The CYA could have been really really high as the previous owner just had a pool service so I doubt it was ever drained and refilled and I know they used the pucks. I'm keeping my fingers crossed as I don't want to drain again.