Salt and FC level in non SWG pool

ljjasper10 · May 23, 2018

The percentage method of FC/cya is a proven method here

so why are there two minimums? Is minimum not minimum regardless of input?

mknauss · May 23, 2018

I assume you all have fully digested this Chlorine/CYA Chart

ljjasper10 · May 23, 2018

Yes and have searched and read most of the ChemGeek articles.

cfherrman · May 23, 2018

Do you know what a sine wave is? The addition of bleach is like the sine wave, when you add it's high and the sun burns it off, when you test the next day you need to be above the minimum. A swg or liquid clorine injection line is more flat, when you test the next day you should be close to the recommended FC, not above the minimum

ljjasper10 · May 23, 2018

That is an excellent analogy and my understand for the reason the “target” for manual chlorination is higher. My question is why are the minimums different?

jblizzle · May 23, 2018

And as we've said before because humans are unreliable. You're free to maintain whatever chlorine level you want in your pool but our minimums are created to provide the least chance of people having a problem

ljjasper10 · May 23, 2018

Look i am not trying to be difficult. I have followed the methods here for a couple of years, but there is a scientific answer to the question. So let me ask the question in a different way

What is the minimum percentage of FC to CYA for alge not to grow.... 10%, 7.5% or 5%. I don’t care how chlorine is added. I have read that 7.5% is the minimum in many locations within the archives. But for a SWG the number is reduced to 5%. Does 5% sanitize properly or 7.5%?

cfherrman · May 23, 2018

I assume that the water that passes through a active cell (or injector) is super clorinated and is more effective killing algae as it passes through

skoum · May 23, 2018

ljjasper10 said:
Look i am not trying to be difficult. I have followed the methods here for a couple of years, but there is a scientific answer to the question. So let me ask the question in a different way

What is the minimum percentage of FC to CYA for alge not to grow.... 10%, 7.5% or 5%. I donâ€™t care how chlorine is added. I have read that 7.5% is the minimum in many locations within the archives. But for a SWG the number is reduced to 5%. Does 5% sanitize properly or 7.5%?

That was the purpose of my post a couple of messages above.

I'll try to run my pool at 5pct for a week or two and see what it looks like...

If algaes start to grow that means indeed the water going through a SWG is kind of "supercharged" compared to the non SWG.