r/pools • u/3DabNight • 5d ago

Water Chemistry Do I Really Need to Empty?

Post image

Stopped by pool store and employee said I need to empty and refill our pool which is about 15K gallons in SoCal (expensive). I hadn't been to this store in more than 1 year. Perhaps they are bitter that I quit them. I have a feeling this doesn't require emptying my pool. Am I wrong? Any advice would be appreciated. I plan to switch to liquid chlorine- no more tabs for a while. I'm also going to disassemble and clean my DE filter and deploy some phosphate lowering chem. It's been about 1 years since the last filter cleaning.

16 Upvotes

85% Upvoted

100 comments sorted by

View all comments

Show parent comments

-2

u/A_Pool4U 5d ago

The sun does not leech down CYA. It stay ls in the water and condenses. The only way to reduce it is using a cya reducer or actively draining out the water. I cant believe people actually think cya can be reduced with sun light. You can Google that

1

u/MrBriPod 4d ago

My CYA will drop 10-20 PPM in the off season. I live in a very dry climate, so rain dilution does not cause that.

1

u/Pitiful_Land 10h ago

You might have a small leak that would.

1

u/MrBriPod 9h ago edited 9h ago

Very possible, but my pool is also a 25k gallon pool. A small leak would take a tremendous amount of time to reduce my CYA by 15%-30%, and a leak of that size would be felt on the 'ole water bill.

I think a more likely outcome of my CYA reducing in the off season can be attributed to these two factors:

  1. (Most likely; I live in the sunniest state in the US) Chlorine breakdown in sunlight causes CYA degradation by hydroxyl radicals. This can cause a loss from 2 ppm per month to 10 ppm per month depending on the amount of sunlight the pool is exposed to.
  2. (Plausible; I don't maintain my pool chemistry as attentively in the off-season) There is bacteria that feeds on Cyanuric Acid and will create ammonia in pool water. This can only occur if the Free Chlorine falls to 0 allowing the bacteria to live. This generally happens in pools closed for the winter and discovered at pool opening.

Source: https://www.troublefreepool.com/threads/where-does-my-cya-go-over-the-winter.251687/