CYA levels

[Nickpooch]

Hey guys,
Just opened the pool a couple days ago. Thanks to you guys a bought a taylor test kit and starting doing the pool by myself. Anyway, opened the pool and it was filled with algae(had to close late due to cover being made). Used liquid chlorine and made it blue but very cloudy. I think I understand why. Here’s my numbers on my 28K gallon pool.

PH: 7.0

Alkalinity : 70

Cya: 100

FC: 11

CC: .5

Calcium hardness: 150

Obviously my CYA is through the roof. I realize I would need my FC to be maintained significantly higher to SLAM.

I’ve begun partially draining the pool in segments. Draining roughly a quarter, then adding new water..etc. Will that work? I don’t want to drain too much as risk messing up the vinyl liner.
Additionally, do you think my CYA is way higher than 100, if so will I have to drain more than 1/2 the pool. How do I test? I read somewhere about diluting in tap water or something?

 

[mknauss]

When you get the pool full and well mixed, run the Extended CYA test.
100 is the limit of the CYA test, so you have to do a diluted test. Mix 50% pool water with 50% tap water. Use this mixed sample as your test water. Multiply the result by 2 for your CYA level.

Then review Draining - Further Reading to see if a water exchange makes more sense.

 

[Nickpooch]

Update:
Seems as though it may be working. Filled 3.5 ML of hose water and 3.5 ML of pool water. CYA came back at 47x2=94 which is a decrease from the initial test of 100. I wish I would have tested that diluted way first though.

 

[mknauss]

So you would be best to exchange around 50% of your pool water to fresh.

You can do that as you have been, might take 3 times. Or do an exchange. Read about that in the link I posted above.

 

[mwemaxxowner]

My cya is a bit high also, at about 70-80. I've been hoping that I could possibly work it down slowly as well. I'm glad to have run across this thread!