High CYA

[Lackey92]

Hi Guys,
My pool has high CYA, ~90. The pool is 35K gallons (non Salt). Everything I have read/seen says I need to drain some water and refill with fresh water. Any ideas on how much water needs to be drained and refilled to reduce the CYA to an acceptable level?

Thanks
Don

 

[Newdude]

Hey Don and Welcome !!!

How are your testing ? Before you drain which is a PITA, you want to be sure.

But to answer the question, fill water has no CYA so it's an even proportion. A 25% drain lowers you 25% and so on. If it's actually 90, 70 us a good start for salt pools and while 40 is best for liquid chlorine, 60 is totally manageable with slightly higher daily FC targets.

 

[Lackey92]

Thanks NewDude,

I'm testing the CYA with the Taylor 2006 test kit, Looking at the black dot in the bottom of the vial. I have done multiple test to make sure I get consistent readings.

I have had a pool service for the last year and every month or so a new kid shows up. So, each new kid gets drilled on what he is doing and why. When questioned about what they are doing, they are clueless. I ask them what chemical and how much they put in and they normally just say about a gallon of this or that. I watch them testing the water, they dip the test vial about an inch into the water, drop in a few drop, put the thumb over the top and shake like heck, then when finished with that test the dump the vial back into to pool right when they get the next sample! It drive me nuts, they don't even know the volume of the pool and just dump chemicals in. Anyways, I should not rant on incompetent pool kids!

I just stared doing my own testing and upkeep and I'm trying to get a handle on this.

The Help and advise is appreciated

Don

 

[Newdude]

I'm testing the CYA with the Taylor 2006 test kit, Looking at the black dot in the bottom of the vial. I have done multiple test to make sure I get consistent readings.

Ok SWEET. You're well on your way.

Try something for me because 90+ is sketchy at best. Mix a batch of pool and tap water 50/50. Use that as your 'sample' and procede with the rest of the test as instructed.

Double the result. If it's still about 90, we'll use that.

 

[Newdude]

I just stared doing my own testing and upkeep and I'm trying to get a handle on this.

We got you my friend. With a k2006 it's like we are testing right besides you and we know what to do from what that says.

You can learn it as we go and we'll be your training wheels.

 

[Chasarms]

The math is linear. If you have a 35K gallon pool and want to get from 90 CYA to 60, drain about 11-12K gallons, or a third of your pool.