I know I've read to be careful about mixing concentrated Muriatic Acid and Liquid Chlorine, including not injecting both through Stenner ports at the same time. How about MA injection with a Stenner following a running SWG? Is the chlorine output from the SWG concentrated enough that a MA injection via Stenner downstream from the running SWG could be a problem?
MA Injection and SWG
- Thread starter trivetman
- Start date
- May 23, 2015
- 25,708
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
No it’s not an issue but injecting acid into a running SWG will almost certainly destroy the catalytic coating on the plates. Most chemical dosing systems manufactured by the major pool equipment manufacturers have control limits in place that avoid dispensing acid while the SWG is running and limits the daily amount of acid dosed to avoid pH crash.
If you’re going to use a Stenner pump to automate acid dosing independent of your SWG automation then I would suggest you place the injection port AFTER the SWG to protect against dosing the SWG while it is running. Make sure your injection port has a check valve on it to avoid acid leaking into the plumbing while the unit is not dosing.
Gotcha. I knew to make the injection after the SWG. By check-valve are you referring to the Stenner duckbill, or an additional check valve on the pool plumbing itself between the SWG and injection port? Maybe both is a good idea.
I'm not planning on a regular timed dosing. My acid demand fluctuates too much. More like a count-down timer to dose as needed. I HATE dragging out the jug of acid once or twice a week!!! I'm going to see how often I have to acid dose this summer and maybe redo the pool pad next year with SWG and convert my Stenner (currently for LCG) into an acid pump.
Then again...we'll see if SWG's continue their meteoric price rise or come back to earth.
Thanks Matt!
I'm not planning on a regular timed dosing. My acid demand fluctuates too much. More like a count-down timer to dose as needed. I HATE dragging out the jug of acid once or twice a week!!! I'm going to see how often I have to acid dose this summer and maybe redo the pool pad next year with SWG and convert my Stenner (currently for LCG) into an acid pump.
Then again...we'll see if SWG's continue their meteoric price rise or come back to earth.
Thanks Matt!
- Jan 4, 2016
- 5,392
- Pool Size
- 44000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
SWCG adds chlorine very slowly, so no worries. Likewise the stenner pump output relative to the flow of swimming pool water in the pipe is quite small.
Main thing is to prevent any acid injection if the pump is not running, so high acidity can not occur near the pump, heater or SWCG. A check valve in the return pipe before the acid injection point would be good insurance to prevent damage if timers failed to prevent same, especially if you have a heater. If it were mine, I'd plumb the acid injection after the SWCG, but it's not uncommon for it to be before the SWCG. Pentair manuals show it before the SWCG, but of course, they're not paying for your replacement salt cell!
Main thing is to prevent any acid injection if the pump is not running, so high acidity can not occur near the pump, heater or SWCG. A check valve in the return pipe before the acid injection point would be good insurance to prevent damage if timers failed to prevent same, especially if you have a heater. If it were mine, I'd plumb the acid injection after the SWCG, but it's not uncommon for it to be before the SWCG. Pentair manuals show it before the SWCG, but of course, they're not paying for your replacement salt cell!
- May 23, 2015
- 25,708
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
I haven’t really considered CO2. Should I? MA just seems simpler and more available and if I convert to SWG I’ve got a spare Stenner on hand. I won’t mind transferring a gallon every few weeks. Its the constant need for a couple cups that gets me
- May 23, 2015
- 25,708
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
A user in FL recently installed a CO2 system that simply doses on a timer based controller. He’s having good success with it. His first 20lbs tank lasted 6 weeks at high usage rate ( break in period). His next tank will likely go longer. If you can located an cheap an easy source of CO2, it’s an option. I’d say a tank or two of CO2 lying around is a bit safer than a 15 gallon container of MA.
- May 23, 2015
- 25,708
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Poolsmith CO2 injection for pH control
Doesn't appear to be much discussion about this system on the forum. Am seriously considering ordering one of these. I'm typically adding about a quart of acid every 3 to 4 days in my 20k gallon SWG pool. Not a lot of fun, plus if we travel for more than a week or so I need to hire someone to...
www.troublefreepool.com
- Aug 23, 2017
- 109
- Pool Size
- 17700
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
I’ve done exactly what you’re wanting to do. Granted I’ve only had it going a few weeks now, but I inject acid after my SWG using a stenner. I dilute the acid 2 gallons to 10 gallons of water, and have it set to inject about 60oz a day. Note, always add acid to the water and not vice versa. I’m still trying to dial it in but it’s getting closer. With the relatively small amount of acid it pumps, a d bring diluted I’m not worried about any long term consequences. Still not into high summer yet, so playing with both SWG % and acid. Probably take me the rest of the season to chart how it behaves. I say go for it 
red-beard
Gold Supporter
- May 27, 2019
- 1,624
- Pool Size
- 25000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite Pro (T-15)
And cheaper. Price CO2 from a welding supply. Much cheaper at the 40/80 lb tank level than equal muriatic acid.