Stenner Liquid Chlorine Chlorinator vs Salt Water Chlorine Generation

[chiefwej]

I was under the impression that the pH inside the cell was much higher than it is in the pool, due to the reaction taking place there. Am I wrong in that?

 

[JoyfulNoise]

Ok, no more big words for me A few years ago when I was having ph issues with my SWG, I read a post by Chemgeek where he explained the process that caused the ph rise... long since brain dumped, so I probably got it wrong.

No, you recollected correctly. SWGs can cause aeration which leads to pH rise but it just depends on the alkalinity level of the water, fill water chemistry and other sources of aeration. There are people who have installed SWGs on their pools and, because they have low alkalinity fill water, they experience no pH rise whatsoever.

 

[JoyfulNoise]

I was under the impression that the pH inside the cell was much higher than it is in the pool, due to the reaction taking place there. Am I wrong in that?

Nope, you are correct. But all of the subsequent chlorine chemical reactions are acidic so, on net balance, the pH remains the same. If chlorine gas is allowed to escape, then that can cause significant pH rise but that only happens when the SWG has a short pipe run to the pool.

 

[RadEngr70]

SWG
pros:
No dealing with lugging bleach around
soft water feel

cons:
Higher initial cost
Added pump run time
Added electricity costs
Added acid demand (may or may not see this in practice)
500lbs. of salt initially
need alternate chlorination when cold
additional test for salt

Stenner
pros:
less initial cost
precise Cl measurement
reduced pump run time
reduced power consumption
year round solution
easier to rapidly increase FC levels

cons:
lugging bleach
maintenance costs (tubes and check valves)

This is a great pro/con analysis... might be a useful sticky post. I'd add in the cons of the Stenner solution - Liquid Chlorine degradation in storage reservoir... especially in hot climates. This can be offset by smaller reservoirs, but means more bleach lugging and less convenience.

Also, the extra electricity costs due to increased pump run times with the SWG solution, are only realized if the SWG your select requires you to run your pump longer than the amount of time your run it for filtration needs. Larger SWGs require less run time to provide the same amount of Chlorine.