CYA Level - Logic for SWG Pools

[muffin_dad]

Why are the CYA levels for SWG pools recommended to be higher?

http://www.troublefreepool.com/content/128-chlorine-cya-chart-slam-shock

Non-SWG goes down to 20, SWG starts at 60.

I'm at ~35 and deciding whether to increase that further or not.

 

[ping]

One of the main benefits is that the SWG will last longer. Try typing that question in the search function and you will find lots responses to this question.

 

[jblizzle]

Basically, the SWG adds FC very slowly and thus needs more protection from the sun to maintain adequate FC levels. This in turn allows the SWG to not have to generate as much FC and prolongs its life.

 

[JasonLion]

CYA levels are a balancing act between lower chlorine usage at higher CYA levels vs more trouble fighting algae at high CYA levels. A SWG significantly changes the odds of getting algae, lowering them noticeably. The SWG also makes using more chlorine rather more expensive. So the tradeoff comes out in a different place.

 

[chem geek]

Also, use of the SWCG tends to have the pH rise so being able to lower its output by losing less chlorine to sunlight due to the higher CYA helps to reduce the rate of such pH rise.

 

[muffin_dad]

Thanks all I'm at 60 now

Sent from my HTC One using Tapatalk

 

[savela]

Higher cya shields chlorine from the sun. Protective effect. Would be hard to maintain such a high sustained level of FC without a swg.