Pool Chemistry Question-CYA

[crdameron]

Please forgive my ignorance in advance. I have been reading through the forums and I haven't figured this out yet and I can't find it in any of the pool school stuff. Where does CYA come from? How does it get into the pool?

I know you can add it to the pool, but if you aren't adding anything, where does it come from? I have read so many threads that say you will have to drain and refill or you will need basically a tanker full of chlorine to combat it-is this a naturally occurring substance?

The only way to combat the CYA is to add chlorine? Correct?

Thanks in advance for humoring me

 

[jblizzle]

The only way it gets in your pool is if you add it. The CYA is used to protect and buffer the FC. It is in some of the solid forms of chlorine (dichlor and trichlor) or it is added separately.

You are not trying to combat the CYA with chlorine. You need to maintain an adequate FC level that is in proportion to the CYA level. If the CYA gets too high, then you have to maintain higher FC levels.

How much Pool School have you read? These should help with your question:
ABCs of Water Chemistry
Recommended Pool Chemicals
How to Chlorinate Your Pool

 

[crdameron]

Thank you-I have read all of those topics in pool school-in fact I have printed them out and they are in my pool school bible now. I just could not figure out how it got in there if you are using the BBB method and you haven't added any. Does that make sense?

I know my test kit isn't in yet but the testing that I have had done in the past few days by the pool place is jumping back and forth like crazy. I know these tests aren't reliable but the differences are HUGE and I wanted to make sure that I haven't done anything to affect those levels in any way. I haven't added anything except liquid chlorine to the pool and won't until I get the proper testing supplies.

I do understand the relationship between FC and CYA and realize that it isn't really combatting but if you have a high CYA level you need to either add more chlorine or drain and refill to get it level again.

 

[RobbieH]

The CYA test is the one test the pool stores have the largest wrong answers for.

 

[crdameron]

LOL good to know! HA HA

 

[Isaac-1]

Most people here do not start off using the TFP method after a fresh pool fill, instead they have either been using the pool store puck feeding method for years and tend to have sky high CYA, or a few have new pools which had their start up often done by their pool builders who added initial (hopefully correct) doses of CYA.

 

[crdameron]

Okay that makes sense. Yes we had been using the pucking Pucks since we moved into the house last year. With the TFP method I am assuming the CYA will go down over time with use, water top offs, and backwashing and then eventually you will need to add some to keep the levels in balance?

- - - Updated - - -

Thanks everyone for the info. I know it is covered in pool school but for newbies sometimes a little clarification is very helpful!

 

[tim5055]

I am assuming the CYA will go down over time with use, water top offs, and backwashing and then eventually you will need to add some to keep the levels in balance?

Water top offs really don't have an effect on CYA as it is usually the result of evaporation. When water evaporates from the pool the CYA level actually rises, although so slightly that you probably couldn't tell.

CYA is lost any time pool water is taken out of the pool, like backwashes, vacuuming to waste, spash out when playing in the pool.

 

[crdameron]

Thank you so much!!


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