Specific shock level?

[mikefamig]

If combined chlorine is gassed off into the air at all FC levels and accelerated by the sun and/or increased FC levels then what is the meaning of "shock level"? The CYA/Chlorine chart here states a specific shock level given a specific CYA level but isn't it true that any increase in FC is going to accelerate the gassing off of CC?

For instance, assuming that my CYA is 50, wouldn't a FC SLAM level of 15 get rid of the CC in time?
as I understand it, it would just take longer than if I had raised the FC to 20 as suggested by the FC/CYA chart. What are the numbers in the chart derived from? Why not SLAM at 30 and get it done faster than at 20?

Mike.

 

[pabeader]

We use 'shock' as a generic way of saying 'higher than normal level' In TFP it is the level that you keep to clear algae and other organics from your pool while SLaMming. It isn't specifically used for CC reduction.

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It is tied to CYA because CYA binds up much of the FC that you put in which lowers the available chlorine. The actual values are derived from % of CYA that produces the needed amount of effective chlorine for the job at hand.

So for 'day to day' you maintain within the lower range but when SLaMming you maintain the 'shock' value.

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You can, of course, go above the recommended levels, but keep in mind that losses to the sun are greater the more you go over.

 

[mikefamig]

Does raising the FC level free up chlorine that has combined with CYA making it available? Is that what shocking is about?

Mike.

 

[mknauss]

Exactly. That is why you have greater FC loss to UV when your FC/CYA ratio exceeds 10% or so.

 

[mikefamig]

Thank you both, I'm trying to put the pieces together so that I can see the big picture and understand why and how things work when they work and fail when they fail.

Mike.