Pentair Optimal Water Chemistry Conditions vs PoolMath

julien2101 said:

Hello Everyone!

I am located in Vegas and run a CYA of 70 and have been shooting for 7.5 FC (I run my pump 24/7 and have been adjusted SWG Dynamically based on expected weather and swimmer load)

It's mostly my wife and I, no kids and pool parties with more than the two of us are relatively rare.

In PoolMath :
- Recommended FC Range for my CYA in Pool Math is 3 to 10
- Ideal CYA is 70-80

In the pentair SWG manual :
- Recommended CYA is 30-50
- Recommended FC 2 to 4 (listing than 4 may cause corrosion of metal components)

I have two questions :
- Why such a discrepency?

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You will see/hear MANY examples of conflicting recommended levels between the pool industry, manufactures, and TFP - most significantly between the FC and CYA relationship. We have LOTS of threads about this issue.

For decades, the pool industry has published very basic level recommendations in an effort to accommodate all pool types and scenarios. We know this to be poor management as pools require different levels based on their type, equipment, location, amount of sun, etc. In some locations, an owner may get by with a moderate CYA of 30-40, while in my area, a summer CYA of 50 is almost mandatory and as low as my water can tolerate.

Along with that, our staff developed the FC/CYA Chart to show owners how those two items should be balanced together to prevent algae. Notice we also separate salt pools in that equation. The pool industry as a whole doesn't make that distinction either (salt vs non-salt).

Just recently I finally saw on the CircuPool SWG site where they recommend a CYA of 60-80. It's a simple concept really, but in the pool industry, they just push one generic group of numbers and that's it. Also remember that the pool industry pushes chlorine tablets and encourages the use of various pool store chemical treatments and weekly super-shocks which are generally not required and/or can cause negative side effects to your water.

Your question has been asked here many times and you can read the various discussions on these threads…

julien2101 said:

- With a range in pool math being so wide (3 to 10), with my pump running 24/7, what is the ideal (meaning sanitize properly but the least harsh possible) FC I should be shooting for?

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Please learn about how CYA buffers chlorine creates active and reserve chlorine. With CYA and FC within TFP ranges there is little active chlorine for harshness.

Read CYA Chlorine Relationship - Further Reading

julien2101 said:

Bonus question : I have a spill over spa, when in spa mode, should I run the SWG?

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Yes, at a lower % then for the pool as the spa is a smaller body of water. Automation systems typically have separate SWG % settings for pool and spa.

Depending on how long you spend in the spa the chlorine can be rapidly consumed by your body secretions. Running the SWG in the spa ensures the water stays sanitary for all in it.

Short stays in the spa may not require additional chlorine.

is the temperature bad for the cell? (my wife likes it at 102...)

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No.