I'm a little confused by the pool math app - "effects of adding" and "FC" are giving me different amounts. I'm trying to move from 5 FC to 7 FC using some 10% liquid chlorine that has weakened to around 5%. FC section of the app tells me to use 94 oz. However, "Effects of" is telling me that 80 oz is enough for that move. I also see the inverse on MA - pH section of the app will tell me a lower amount than "Effects of" says I need to move to my desired pH. I'm confused about the discrepancy between the two areas of the app and unsure which one to rely on for chemical dosing.
A little confused by pool math app...
- Thread starter atxjmy512
- Start date
- May 3, 2014
- 58,369
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
I entered your data based on your Poolmath logs and I cannot match your results.
The chlorine add by touching FC or using Effects is the same on my app.
The chlorine add by touching FC or using Effects is the same on my app.
This is what I see
I think what I'm seeing is specific to 4%. If i change strength to 5% - its much closer.
- May 3, 2014
- 58,369
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
I used 5% for the chlorine. I do not think 4% will work. The calculations do not work for all %'s, just those that are in normal levels known to be sold. You are better off to enter 10% and then do your own changes due to diminished product.
Yes. That's what I'm trying to do. I add, test to see how close i get get to expected FC lift, and then adjust strength based on that. Was hoping I could just plug the adjusted strength into the app and have it tell me how much to add. I'll keep trying. Thanks!
- Feb 6, 2015
- 6,096
- Pool Size
- 12300
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Just leave it set at 10% (cause that is your default percent that you use). If you think yours has degraded to about 5%, just double the amount shown for 10% - it will be close enough. Then if you want to know the exact amount it added, retest the FC in about 30 minutes with pump running. If low, add more - if high, just leave it as it won't hurt anything.
Always dose for the high end of the target range for a given CYA. For your CYA of 50, that would be FC 8.
Always dose for the high end of the target range for a given CYA. For your CYA of 50, that would be FC 8.
The challenge i run into is that after retesting - most of the time weakened chlorine comes in at around 6.5%. If i'm expecting a jump of 1.5 ppm, and i get 1.0ppm - 2/3 strength. That's not always easy, chlorine bottle in hand ready to pour math unfortunately.
- Feb 6, 2015
- 6,096
- Pool Size
- 12300
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Put more in - if the result comes out higher than target, don't worry about it. It is safe to swim with an FC between minimum and SLAM level for your CYA.
The only considerations are - pH test isn't valid when FC is >10 and you have to be able to see the entire pool bottom.
With degraded chlorine, you really don't know what the exact percentage is (same holds true for fresh chlorine actually). You put some in (a best guess), retest and add more to get to your desired target if needed.
It's never going to be an exact science as the pool environment is ever changing.
The only considerations are - pH test isn't valid when FC is >10 and you have to be able to see the entire pool bottom.
With degraded chlorine, you really don't know what the exact percentage is (same holds true for fresh chlorine actually). You put some in (a best guess), retest and add more to get to your desired target if needed.
It's never going to be an exact science as the pool environment is ever changing.
