New to Pools -- Interested in Liquid Chlorine

[wmitz]

Hi, i'm trying to sign up in the new users forum but got sent here. I'm thinking about switching to liquid chlorine, but am wondering if one needs to balance the high pH in the 12% liquid chlorine.

[PoolDoc]

You got as far as you get, on the first pass. I split your post off into its own thread, and moved it here.

You have to 'balance', or compensate for, the pH effects of ALL forms of chlorine you can use in a pool: gas, bleach ('liquid chlorine'), cal hypo, dichlor, trichlor, SWCG (salt water chlorine generator). But the overall pH effect of bleach is smaller than that of any of the other forms of chlorine.

[waterbear]

ALL forms of chlorine are net acidic when they are "used up" (have an acidic reaction when they act as a sanitizer/oxidizer) so the unstabilized chlorine sources (liquid chlorine, cal hypo, lithium hypochorite) , which are alkaline on addition are pretty close to pH neutral in actual use so you really do not have to compensate.
On the other hand the stabilized chlorine sources (dichlor and trichlor) are acidic on addition (particualrly trichlor, which is extrememly acidic) and also acidic when they react so you DO have to compensate for the acid constantly added to the pool by monitorng pH and TA closely and regular additions of alkalinity increaser (baking soda); and pH increaser (sodium carbonate, washing soda) or borax.\

The MAIN cause of pH rise in any (not counting new, curing plaster) is from outgassing of carbon dioxide and this can be mnimized by lowering the total alkalinityif using an unstabilized chlorine source.

[PoolDoc]

I hid Waterbear's post yesterday, so we could discuss it; we don't quite agree. Unfortunately, when we tried to check with an authority, we got conflicting answers, so it's still not quite resolved.

What we agree on, is this: you will NOT have to do nearly as much pH adjustment if you use bleach, whether 6% household bleach or 10 - 15% commercial bleach, as you would with more common forms of chlorine such as dichlor powder or trichlor tabs or granules.

Contrary to what most pool stores (and pool operator training programs) teach, in actual practice, bleach requires very, very little pH 'compensation'

I actually operated one very large commercial pool (about 350,000 gallons) for THREE YEARS without using ANY acid at all.

[waterbear]

What we agree on, is this: you will NOT have to do nearly as much pH adjustment if you use bleach, whether 6% household bleach or 10 - 15% commercial bleach, as you would with more common forms of chlorine such as dichlor powder or trichlor tabs or granules.

Contrary to what most pool stores (and pool operator training programs) teach, in actual practice, bleach requires very, very little pH 'compensation'

I actually operated one very large commercial pool (about 350,000 gallons) for THREE YEARS without using ANY acid at all.

And I have had similar experience myself on a 55k and a 60k commercial pool. that needed very minimal acid while, at the same location, a 1k gallon kid's "play and splash" area (which were multiple water features that drained into an underground tank) needed constant acid additions because of the amount of aeration that cause constant pH rise from CO2 outgassing. We used acid pumps to automate this but we used a lot of acid in the splash area and very little in the pools. We used liquid chlorine to sanitize and also as shock on all three.