Best chlorine tabs to use?

[land21]

From reading there is no way to reduce the CYA unless you drain the water--however, using the Cal-Hypo which would be "shock" would increase the calcium hardness-but it can be reduced without draining the pool--correct?

Liquid the best--but need to add more frequently...the next best would be Cal-Hypo?

Am I understanding this correctly?

Thanks

[chem geek]

You can't reduce calcium hardness (CH) without water dilution -- at least not easily (one can partially sequester it to prevent scaling and one can precipitate it using oxalic acid, but that's messy). Chlorinating liquid and bleach do not increase CYA nor CH.

On a percentage basis, the rise in CH from Cal-Hypo is slower than the rise in CYA from Trichlor or Dichlor so in that sense it is "better" unless your CH is already high. As for frequency of addition, you have to add Cal-Hypo just as frequently as any other chlorine unless you have a special chlorinator designed for Cal-Hypo tabs (such a chlorinator being very different than the one used for Trichlor).

[Ralph Figueroa]

A certain Pool Supply company, starting with an L, makes the claim that their "chlorine tabs are the STRONGEST in the market." Help us all cut through the marketing crap and make a good decision! They say they have 90% available chlorine. Most of the containers of chlorine I have bought on the market say 93.5-94% Tri-Chlor. Give us the breakdown...Please!

[chem geek]

Actually, typical Trichlor tabs/pucks are 99% Trichlor which is roughly 89-90% Available Chlorine so I don't know which ones you are using (see . However, that's pretty pointless unless you are concerned with how much weight you are carrying when buying chlorine. 12.5% chlorinating liquid or 6% bleach can be less expensive per FC than Trichlor when accounting for the pH adjusting chemicals needed for Trichlor. Of course, with bleach or chlorinating liquid, you have a lot more weight to carry, but they do not increase Cyanuric Acid (CYA) levels. See Cost Comparison of Chlorine Sources though that post is older so prices are not current (but the way the calculations are done is still valid).

Look at poolgeek.com and see that Trichlor products from GLB are 99%. The 93.9% are BioGuard Silk Sticks because they have additional ingredients.