SWG production of FC in ppm?

[Subscribe1028]

If an Intellichlor IC20 produces 0.70 lbs of pure chlorine every 24 hours on a 100% setting (per the manual), would that equate to about 4.0ppm of FC in a 20,600 gallon pool?

Here's my math:
ppm = mg/L
.70 lbs = 317,514 mg
20,600 gallons = 77,979 L
FC ppm = 317,514 mg/77,979 L = 4.07 ppm

What does "pure chlorine" mean? 100% chlorine?

So does this mean running my IC20 at 100% 24 hours per day would produce about 4.0ppm FC? I'm having a hard time with maintaining chlorine levels, just finished a SLAM on Sunday morning and have to start again because water is cloudy again. My CYA is between 20 and 30 (calling it 30 with rounding up) and I know I didn't let my FC drop below 2.0 because I've been testing like a maniac, and I never got a reading below 5.5 since I finished the SLAM until tonight it was 2.5. Waaaaaa. Help. I know the SWG is undersized, but replacing it right now isn't an option. Thus, I think I'm going to have to manually dose with some LC daily and I'm trying to get an estimation of how much I need to stock up on to get me through another 8-10 weeks of pool use before we close up for the season.

 

[Jimrahbe]

s,

Your answer of 4.1 is correct, although I just went into Pool Math and entered 20600 at the top and then looked in the effects of chemicals box and selected Chlorine Gas and 11.2 oz.

With a SWCG your CYA should be up around 70 or 80.. If your CYA were correct than running your cell 24/7 at 100% just might be good enough to produce the chlorine you need.

But you need to jack the FC up with liquid chlorine first to about 5 or 6 ppm and then let the SWCG take over...

Thanks for posting,

Jim R.

 

[Subscribe1028]

Thanks, I wasn't sure if "pure chlorine" was the same as "chlorine gas" in the pool math calculator...though I suppose I could've checked my answer there to see if it made sense selecting chlorine gas as the source

I know on the CYA, was trying to get through the SLAM and stabilize before adding more CYA. I've added 7 lbs via the sock method so far this season and my CYA is still only 30 (between 20 and 30, going with 30, used 2 different test kids the K2006 and the Pentair rainbow CYA test kit). It should be at least 40 according to pool math, and I'm definitely reading it properly....even got the second test kit bc I wasn't sure.

Do you think for this SLAM I should just use CYA of 40 bc I know I added that much since opening late May of this year? My last addition was well before my most recent reading (at least a week, I'd have to check my logs for exact dates).

Thanks!

 

[mknauss]

You can use 40 ppm CYA for this SLAM if you like. It will not hurt.

The loss of 5 ppm of CYA per month during summer is not unusual. So if you have put in 40 ppm worth and are reading 30 ppm that works as we are more than 2 months into summer.

You do need to run your SWCG 24 hours per day at 100% to maintain your FC. And that is with CYA near 70 ppm.