Unclear about Poolmath numbers

[aperakh]

Confused about the number for FC on PoolMath.
Populatign the table with the recomended numbes, it enters 28 for the recommended lever for FC at the 1st row of the table.
What units is that in. becuase my test kit, also from TFP, uses ppm and the reomended numbers aren't even anywhere close to that figure. Same for the 2 sets of 3rd party test strips.

Yet, below the table in the notes uner: "Effects of adding chemicals" the number do seem a bit more in line with ppm. And in any case, why are there two different places of calculation how much chlorine to add?

- New and Clueless

 

[YippeeSkippy]

Most swimming pool tests/chems deal in ppm- parts per million
Were you by chance reading the column for SLAM level of FC? That chart line lists needs to kill algae, based on your CYA level.

How are you chlorinating?
How do you normally test?

Here are some basics that ought to be help for you:
Pool Care Basics

Holler back here with any other questions

Maddie

 

[YippeeSkippy]

 

[Newdude]

Right above the '28', toggle the SLAM option off. You turned it on by mistake. My fat fingers do similar all day long.

If you are adding liquid chlorine, is your CYA actually 70, or was that a mistype also

And in any case, why are there two different places of calculation how much chlorine to add?

I like to click the FC tab and do it that way. i tell it i want to go from 4 now to 9 after adding and it tells me to add XXX ounces.

'Effects of adding' is kind of reverse engineering where you tell it you added XXX ounces and it tells you it would raise X by Y. Most use it when they wonder what a specific add will do, not to see how much to add.

Both tell you the same thing in the end.