Too cold for SWG - Next steps

phishphan

Member
Jan 26, 2021
14
NC
Water dropped below the temp threshold and SWG automatically turned off and since I keep my pool open all year for cold dips so it's time to manually add chlorine.
Last year I was buying plain bleach and adding it accordingly but I'm wondering if anyone has already done the math on the cost difference between buying liquid chlorine and powdered chlorine.

Thanks!
 
I havent done the math, but please also consider the impacts of powdered chlorine as it will add CYA or Calcium depending upon specific the product.

I personally will use all 3 (liquid, trichlor pucks - adds cya, and powdered shock - adds calcium) over the winter to replenish my CYA and Calcium as needed, but only after testing my water and making sure I can afford to have my CYA or Calcium increase. Once I get those numbers where they should be, I will exclusively use liquid chlorine.
 
Granular chlorine will add CYA (Dichlor/Trichlor) or Calcium (Cal-Hypo) to the pool when you use it.
If you understand the first sentence, and can manage CYA and CH, you can use whatever product you like.
You don't want to add too much CYA or CH...the only way to lower them is to replace water. Not fun.

Prices from In the Swim:
Trichlor $359 for 50 lb. = 7.18 per pound, will raise FC by 10 per lb. So, $0.718 per FC. Each pound will also raise CYA by 6ppm.
Dichlor $217 for 40 lb. = 5.425 per pound, will raise FC by 6 per lb. So , $0.904 per FC. Each pound will also raise CYA by 6ppm.
Cal-Hypo (68%) $260 for 50 lb. = 5.2 per pound, will raise FC by 7 per lb. So, $0.742 per FC. Each pound will also raise CH by 5ppm.

Ace, CDS 10% Liquid, $7.60 per gallon, will raise FC by 9.1. So, $0.83 per FC. Will not add CYA or CH.

Best to use granular sparingly, and only when you need CYA or CH. Stick with liquid all other times.
 
Granular chlorine will add CYA (Dichlor/Trichlor) or Calcium (Cal-Hypo) to the pool when you use it.
If you understand the first sentence, and can manage CYA and CH, you can use whatever product you like.
You don't want to add too much CYA or CH...the only way to lower them is to replace water. Not fun.

Prices from In the Swim:
Trichlor $359 for 50 lb. = 7.18 per pound, will raise FC by 10 per lb. So, $0.718 per FC. Each pound will also raise CYA by 6ppm.
Dichlor $217 for 40 lb. = 5.425 per pound, will raise FC by 6 per lb. So , $0.904 per FC. Each pound will also raise CYA by 6ppm.
Cal-Hypo (68%) $260 for 50 lb. = 5.2 per pound, will raise FC by 7 per lb. So, $0.742 per FC. Each pound will also raise CH by 5ppm.

Ace, CDS 10% Liquid, $7.60 per gallon, will raise FC by 9.1. So, $0.83 per FC. Will not add CYA or CH.

Best to use granular sparingly, and only when you need CYA or CH. Stick with liquid all other times.
Very much appreciate your math. I have a vinyl inground so calcium not an issue. I haven't adjusted my CYA since mid-summer so I am likely low. Looks like liquid is the way to go and I'll integrate a few pucks to raise my CYA. Appreciate ya'll.
 
I have a vinyl inground so calcium not an issue.
You can get calcium scale, particularly in your SWCG, and even on the liner if your CSI gets too high...Calcium is one driver of CSI...The only way to lower CH is to replace water.
Do you use Pool Math? If so, go to gear in upper right, turn on TRACK CSI and TRACK Temperature, and enable sharing with TFP (Make sure you use the same login ID/PW as TFP...then we can see your logs).
 
You can get calcium scale, particularly in your SWCG, and even on the liner if your CSI gets too high...Calcium is one driver of CSI...The only way to lower CH is to replace water.
Do you use Pool Math? If so, go to gear in upper right, turn on TRACK CSI and TRACK Temperature, and enable sharing with TFP (Make sure you use the same login ID/PW as TFP...then we can see your logs).
I don't use Pool Math but I know my calcium is low because my metal fins have little to no scale on them every time I pop the hood on the SWG. After 20 minutes in a vinegar soak they're like brand new. I also oversized my salt cell so I only have to run it at 35% capacity during peak swim season. That was one of the best build decisions I made and I recommend the same to anyone in the market for a new one.
 
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