The Great Tetraborate Experiment!

[chem geek]

Is it possible that the sodium released by the salt cell is being bound by boric acid as it leaves the cell? It seems like that would increase the performance of the SWG by reducing the amount of chlorine that binds back to the free sodium in the water. If the SWG is having to work less, then obviously the pH of the pool will rise less slowly as well.

Nope, that doesn't make sense chemically. First, sodium is not released by the salt cell. The salt cell doesn't do anything with the sodium ions that are in the water, except that they help the conductivity of the water itself to help carry (balance) charges from one plate to the other. The salt cell simply converts chloride ion into chlorine gas and this chlorine gas dissolves in the water to produce disinfecting chlorine (HOCl). See this post or this post for more technical details.

The main way that Boric Acid (borates) may help reduce chlorine consumption is in inhibiting algae growth. It is well known that Boric Acid will inhibit algae growth (see this link) so with less algae growth, there is less algae for chlorine to kill or deactivate. I am surprised that this results in a measurable decline in chlorine usage since I didn't think the killing of algae in "clean" pools consumed very much chlorine at all, but I could be wrong. I thought that the bulk of the chlorine consumption was from the breakdown from sunlight and I doubt that Boric Acid has anything to do with reducing that process, though if it does (which I believe is unlikely), then I have the concern that it might operate the way that CYA does and bind to the chlorine making a new compound that is essentially ineffective as a sanitizer.

Richard

[sailork]

Doh! I really was forgetting my basic chemistry!

[Spensar]

Found this link in some old bookmarks. I haven't used them, am not related, etc., but it is an interesting site that sells bulk chemicals, including borax. You can get a 55 pound bag for $1.35/lb. + shipping. Not sure how this stacks up with 20 mule team on sale, but you won't have all those boxes.

http://www.chemistrystore.com/borax.htm

[mbar]

I have used the chemistry store to buy ascorbic acid - they are very dependable, and will even answer any questions you have. The chemicals are delivered quickly too.

[mbar]

Have you tried Lowes? I know they sell it, so you can order it online from them.

[sailork]

I get mine at Home Despot. I think there are some shipping restrictions on the stuff so it might not be so simple to order.

Oh, and I'm pretty sure that swimming pools are the most common usage so look on the "pool aisle."

[waterbear]

Ace Hardware also usually carries it...and you can get it in just about any pool store. In my area one of the pool stores (NOT the one I work at) has the best price I have been able to find....so don't rule out the pool stores, it is possible to shop in one without getting "poolstored"!