# Solved: Help an Aggie understand PoolMath SWG math

#### dntboles

##### Well-known member

Some might say I should be brilliant at math, considering how many times I took it at Texas A&M. Although the number of times taken is greater than the number of times passed...

Reading a forum reply, I learned the PoolMath app can suggest a SWG setting so I decided to test it out, but I'm a little confused by some of what it's telling me.

SWG = IC-40
Pump and SWG run 4 hours per day
Typical output is around 60%, but varies. We've had lots of rain. We also have trees (good for shade, bad for leaves).
CYA = 70

When I went to log a chemical addition and told it SWG, I set 24-hr output at 1.4 ppm, based on the in-app chart. I set pump run time to 4 hours and SWG% to 60. Poolmath said the FC generated would be 1.1 ppm. That's where I'm confused by the math.

So I set it to run at 100% for 24 hours and it would produce 11.0 ppm. That seems way too high, for an SWG that creates 1.4 ppm per day for a 40K gallon pool.
What am I missing?

#### wireform

Silver Supporter
In The Industry
The 1.4 is not ppm but pounds per day

#### dntboles

##### Well-known member
I figured this would be something simple! Thanks for the clarification.

I'm just past 2 months of SWG use and loving it. I didn't know I could log "chemical additions" for SWG but I've been tracking my settings in Google Sheets, just to try to dial in where I need to set it. Of course, it changes over time with increased UV in the summer, all the rain we've had, the leaves falling from the hail storms, etc.

Thank you

#### TexEdmond

Gold Supporter
I was trying to figure out why my math was so off while calculating my spa side SWG percentage runtime. The error was me grossly miscalculating the volume of the spa... I had forgotten the volume of a cylinder is not calculated by squaring its diameter, it's the radius. I is an Aggie too.

Whoopgigemhowdywhoop.

dntboles
Hello , This is an inactive thread. Any new postings here are unlikely to be seen or responded to by other members. You will get much more visibility by Starting A New Thread

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