liquid chlorine versus powder

[purplegirl]

The kid at the pool store told me that dry chlorine is better than liquid because it is 64% active versus the 6% active liquid version. Is this true? Is powder chlorine better than liquid? or is that another pool store antic to get you to spend more money?

[waterbear]

1 gal of 12.5% liquid chlorine raises 10000 gallons of water about 12 ppm

1 gal of 6% liquid chlorine (or laundry bleach) raises 10000 gallons of water about 6 ppm

1 lb of 48% cal hypo (the most common strength that is sold as pool shock in 1 lb bags these days, the stronger stuff is getting hard to fnd since it is a class III oxidizer) raises 1000 gallons by about 5 ppm

lb of 65% cal hypo ( getting hard to fnd since it is a class III oxidizer) raises 1000 gallons by about 7.5 ppm

1 lb of 73% cal hypo (A strength that I have not seen in several years!!!) raises 1000 gallons by about 8 ppm

IF you compare the costs:
a gallon of pool chlorine in my area is about $2 ==>best value
A gallon of laundry bleach is about 1.50 ==> second best value
A 1 lb bag of 48% cal hypo is $4-$6 ==> expensive!
A 1 lb bag of 65% cal hypo is $4-$6 ==> expensive!
73% cal hypo does not seem to be available anymore in my area,
YMMV since there are regional price variations.

[Watermom]

No. The kid at the pool store probably has absolutely no experience with pools. He probably saw the help wanted sign on the door and BOOM. He is now a "pool expert."

[waterbear]

No. The kid at the pool store probably has absolutely no experience with pools. He probably saw the help wanted sign on the door and BOOM. He is now a "pool expert."

That's how I started in a pool store!

[aylad]

Not only is the powdered version more expensive, but they didn't even mention the issues with clouding from undissolved powder, or milky water from excessive calcium levels, or staining from undissolved powder sitting on the pool floor......

Janet

[CarlD]

That's how I started in a pool store!

This could be a Marx Brothers routine! "When I started out I didn't have a nickel in my pocket. Now I've got a nickel in my pocket!"

[purplegirl]

Thanks waterbear for the detailed explanation. I understand now.

[chem geek]

The powdered and puck forms of chlorine are more concentrated per WEIGHT so you have less to carry, but they are far more expensive per pound such that they are not all less expensive and as was pointed out some are quite a lot more expensive.

The main problem with the other forms of chlorine is what else they add to the water. The following are chemical rules of fact that are independent of product concentration or of pool size:

For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm.

[purplegirl]

So if I have a vinyl liner and I add cal hypo I don't have to worry about the CH, right?

[Watermom]

You can use cal-hypo for awhile but if you use it exclusively for a long time, then the calcium hardness level can build up and you can have cloudy water issues. That won't happen for awhile so if you want to use it some, you can.