Adding chemicals to a new pool

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Adding chemicals to a new pool

Postby Guest » Fri 22 May, 2009 10:13

I am just starting an above ground 15' round pool. I want to know how to add the chemicals. I need to add alkalinity plus calcium hardness, shock and CYA. I need to add a lot of chemicals and I need to space them out What's the best way to add them. Thanks Colleen

chem geek
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Adding chemicals to a new pool

Postby chem geek » Fri 22 May, 2009 13:15

Read the Pool School including Recommended Pool Chemicals .

The TA is increased with baking soda (or Alkalinity Up) and can be added anytime, but don't overdo it. The appropriate TA level depends on the type of chlorine you will be using. Hypochlorite sources of chlorine, including chlorinating liquid and bleach, should have a TA of around 80 ppm while when using Trichlor tab/pucks one should have the TA higher usually around 120 ppm or more.

You can increase Calcium Hardness (CH) using Dow Peladow or DowFlake (or Calcium Hardness Increaser), but you could also use Cal-Hypo as your source of chlorine for a while if you don't need to raise the CH by very much or that quickly. For every 10 ppm Free Chlorine (FC) added by Cal-Hypo, it also increases CH by 7 ppm.

CYA is slow to dissolve so you can put it into a sock or stocking and hang it over a return with the pump running. Or you can add this to the skimmer with a skimmer sock, stocking, T-shirt, etc. IF you have more than one intake (i.e. skimmer of floor drain) to the pump or if your skimmer has a bypass. Doing it this way has the CYA dissolve in around 8 hours. If you add CYA directly to the skimmer without a sock/stocking/shirt, then it will get caught in the filter and take days to dissolve.

To increase the CYA level, you could also use stabilized chlorine for a while, either Dichlor powder/granular which dissolves quickly or Trichlor pucks/tabs that dissolve slowly. For every 10 ppm Free Chlorine (FC) added by Dichlor, it also increases CYA by 9 ppm. For every 10 ppm FC added by Trichlor, it also increases CYA by 6 ppm.

You can use The Pool Calculator to figure out dosing and to calculate the saturation index which will tell you how much CH you need relative to the other parameters.

Keep in mind that if you plan to use Trichlor as your primary source of chlorine, that the CYA level will rise over time so you'll need to use a supplemental algaecide (weekly PolyQuat 60) or phosphate remover (both at extra cost) to prevent algae growth. If you don't want to go this route, then you could just add chlorinating liquid or bleach, but will need to do that every day or two so it's less convenient (unless you have a pool cover in which case you can often add chlorine twice a week).


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