FC/CYA Level

[pgjohnson]

Hi,

Just a general question as hoping to understand my pool better.

File:FC CYA Chart.png - Further Reading

www.troublefreepool.com

Looking at the chart above for FC/CYA Levels, what happens if the pool is at the minimum level for a week or two, is that bad. Obviously will be checking constantly and trying to keep in target range but was wondering why there is a minimum and target range. Would algae occur if left at minimum because the CYA is holding onto all the free chlorine? Or once it reaches minimum it is release by the CYA?

Thanks

 

[Mdragger88]

Keeping fc at minimum or above for your cya should prevent algae if there’s none to start with. However, Skirting minimum is not recommended which is why there’s a recommended target range.
The cya binds a % of the “active” chlorine at all fc levels- when fc is below minimum on the chart the amount of active chlorine is simply too low for effective sanitation & nasties can grow.

 

[pgjohnson]

Awesome, thanks so much. So as long as above minimum all good.

Also does pump speed affect chlorine production, I have a variable speed pump that usually runs on low speed. I would presume not and it just affects turnover of pool water.

 

[Mdragger88]

If you’re concerned that something funky may be brewing from your time playing kissy face with minimum you can always do an Overnight Chlorine Loss Test to confirm or deny a problem.

I presume you mean chlorinating with a salt water chlorine generator?
If that’s the case, So long as you’re running the pump at high enough rpm to engage the flow switch production will be the same (based on your percentage setting & time) no matter the speed.