Calculate amount liquid acid to liquid chlorine?

Blowout

Well-known member
May 13, 2012
160
San Jose, CA
I've just installed a Stenner pump/tank for chlorine dispense and everything is working fine. Running 15 min/day with fixed rate pump and free chlorine is stable at 5ppm.

Still have to manually add liquid acid regularly so looking to automate that as well and in the information gathering phase now... likely use a Stenner pump/tank.

Contemplating using the same timer as the Chlorine pump and diluting the acid to a concentration that will offset the pH change from the Chlorine.

I understand that the CY and pool size becomes a variable in this calculation, so not sure if this is even a viable approach. Just trying to eliminate another timer and the need to adjust acid dispense time independent of the chlorine feeder.

Anyone know of a calculation chart of chlorine concentration to acid concentration? It would be really nice if it was a calculator, but might be asking too much there :)

How do folks normally approach acid and chlorine dispense?

I suppose another way would be to use a variable speed Stenner pump and adjust volume on the acid that way using the same timer. Any thoughts with this approach?
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
43,238
Tucson, AZ
The pH rise that you need to combat has nothing to do with the chlorine you are adding. Bleach is effectively pH neutral in that while the pH may go up slightly when it is added, the pH will go back down when it is consumed.

The pH rise is more attributable to having plaster, aeration, and high TA driving up the pH. The pH change is going to vary depending on those factors. As the TA comes down (as it will with acid addition, unless your fill water TA is very high) the pH rise should slow down.
 

Blowout

Well-known member
May 13, 2012
160
San Jose, CA
I was told the liquid chlorine was causing the requirement for acid, so that information from Leslies was wrong it sounds like. I'm constantly adding acid to balance the pH.

TA is now 70.
 

Blowout

Well-known member
May 13, 2012
160
San Jose, CA
Seems running the 2 injection systems unrelated to each other would make the most sense then.

Probably dosing into the same pool return line at different times would be best as well.
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,875
San Dimas, CA (LA County)
If you concentrate on lowering the TA to 60+/- 10 you'll probably discover that you can get by with weekly acid additions, which isn't such a terrible burden. It might add 60 seconds to your weekly test routine.