Discrepancy in Pool Math app

[AW139]

I’m just running the numbers using the Pool Math app for my SLAM that I’m going to start today. My pool is 30,500 litres.

Using the “Effects of Adding” page, it tells me with my pool size adding 3660 ml of 10.3% chlorine will raise my levels by 15 ppm.

If I go to my pool and click on then Free Chlorine tab, SLAMing my pool from 5 ppm to 20 ppm is telling me I need 4438 ml.

I know this isn’t a massive difference, but it’s still over 20%, and I want to try to be accurate.

 

[proavia]

What is the result if you use 10% instead of 10.3% in "Effects of adding"?

 

[AW139]

What is the result if you use 10% instead of 10.3% in "Effects of adding"?

Amazing, thanks. I changed both tabs to say 10% instead of 10.3%, and now they match up. Appreciate the help.

 

[proavia]

Great!
I believe PoolMath probaby works best with 10%, 12.5% and other relatively 'standard' chlorine percentages.
10.3% isn't a 'standard' percentage we see here in the US.

Your results still may be a little off, especially if your pool volume is a little higher/lower than you think. Also, the age of the chlorine and how it is stored is important - as chlorine percentage degrades with time and warm temps.

Close is close enough. You can always dose and retest to see if you attained the target you were looking for.

 

[AW139]

Great!
I believe PoolMath probaby works best with 10%, 12.5% and other relatively 'standard' chlorine percentages.
10.3% isn't a 'standard' percentage we see here in the US.

Your results still may be a little off, especially if your pool volume is a little higher/lower than you think. Also, the age of the chlorine and how it is stored is important - as chlorine percentage degrades with time and warm temps.

Close is close enough. You can always dose and retest to see if you attained the target you were looking for.

Thanks. I was using the percentages on the bottle instead of the standard 10%. Once I adjust to 10%, things lined up.

I actually got the exact volume of the pool from the manufacturer this morning, and am using that number for my current SLAM process going on right now. I bumped from 7 FC to a target of 20 FC using the volume of chlorine dictated by Pool Math, and ended up at 21 FC. Pretty close, with only a 5% margin of error. I’m sure my measuring of chlorine plus any error in testing could make up for a 5% error.

Age of chlorine is just something I will have to deal with. Add chlorine, test, and add more if needed like you said.