Re-purposing Aerobic Septic Venturi Chlorine dispensers as Pool Chlorinators?

skola28

Active member
Jul 16, 2020
25
Dallas, TX
We recently had to install a new septic system, and it includes an automatic chlorinator which uses the pressure generated by flowing fluid to draw chlorine out of a holding container, and add measured amounts into a disinfecting chamber inside the septic tank.

This is essentially the same function as adding chlorine to a pool, and so I'm wondering if anyone has repurposed one of these septic systems for pool chlorination? Essentially, when the pump is running, the flowing water would pull bleach out of the holding tank and into the pool return water.
Here is an example:
And an example of someone installing a DIY version
1600365597608.png
Above is a picture of a 'full system' --- the big green pipe is just a bleach reservoir.


Pros:
  • Much cheaper than the Stenner Pump method
  • No moving parts
  • No electricity/power
  • No/extremely low maintenance compared to SWCG and Stenners
Cons:
  • Less accurate than the Stenner method (maybe not as important as we think)
  • May require modification to your pump duration/schedule (not sure b/c I don't know upper/lower limits on liquid bleach dispense rate)
  • Likely will be compared to "The Liquidator"
Also, the Stenner method is WAY overkill on accuracy --- without an automated system which senses the actual pool chemistry and subsequently adjusts the dosing, that level of accuracy is not useful. This is because all of the other factors which affect the pool chemistry are NOT controlled for: Sunlight, Temperature, Usage/Demand, Rain/Weather, etc. For the pool owner who just dumps a gallon of beach into the deep end every couple days, this could be a cheap useful solution. Chlorine levels low b/c of a party? Just run the pump longer.
 

cowboycasey

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Jul 3, 2013
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Fletcher, OK
exatly the same as "The Liquidator" also adds CYA at all times and you will be in trouble just like everyone else using the "The Liquidator"..
 
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Texas Splash

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TFP Expert
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Well, hats-off for creativity. :salut: I can relate as I just replaced our aerobic septic after only 14 years. Ugh. That was expensive disappointment ($,$$$). I actually kept my pump and still have the purple vertical discharge pipe attached, just trying to decide if I should keep it for an emergency pump. If we assume the siphoning process works reliably as for a pool system as it was designed for the septic, someone would still need a way to control how much gets siphoned. The older ClearStream tanks had a ball valve under the lid at the reservoir for that purpose, but you would need to control flow and/or pump run time. I'm unclear what you meant above by "without an automated system which senses the actual pool chemistry" , but neither the Stenner or Liquidator sense chlorine levels. We still have to test our FC level, and for us at TFP, accuracy is everything. So if someone was to attempt this option, they would have to really watch their FC level closely for a while to see if it maintaining the FC level as designed. But hey, if you try it, let us know how it goes. :)
 
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skola28

Active member
Jul 16, 2020
25
Dallas, TX
"without an automated system which senses the actual pool chemistry" , but neither the Stenner or Liquidator sense chlorine levels.
I really am just pointing out that the Stenner system has to be continually adjusted, even though it has ridiculously precise metering capability. The reason it has to be continuously adjusted, is because of all the 'pool environment unknowns'. In the end, I'm trying to say that the accuracy of the Stenner systems isn't really an important parameter when it comes to comparing Stenner vs 'Septic Venturi' because FC has to be continuously monitored and adjusted for both. Clearly if you bought one of those automated water tester computers as a feedback loop, you'd be much better off with the Stenner.

I may try it out and fill the unit with a measured amount of water first. Run the pump for 8 hours, and record how much of the premeasured water is left. Repeat a few times to see what kinda flow I can get.

Also, the 'Septic Venturi' system that I have is adjustable, so once I get an idea of how much bleach it dispenses per hour, at 'x' RPM, I should be able to dial in dosages. And really it shouldn't run more than about $30 in parts....
 
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skola28

Active member
Jul 16, 2020
25
Dallas, TX
exatly the same as "The Liquidator" also adds CYA at all times and you will be in trouble just like everyone else using the "The Liquidator"..
I don't think I understand. This method should only add Liquid Bleach --- no CYA/Stabilizer at all. All the other chems would need to be monitored/adjusted as usual.
I also think its different from the 'liquidator' as it doesn't have a mixing vat of bleach/pool water. When the pool pump turns on (ie: high pressure water flowing through pool returns) venturi pressure pulls bleach out of the storage tank and injects it into the pool return lines. When the pump stops, the bleach just sits in its bleach container.
 

cowboycasey

Gold Supporter
LifeTime Supporter
TFP Guide
Jul 3, 2013
4,448
Fletcher, OK
I don't think I understand. This method should only add Liquid Bleach --- no CYA/Stabilizer at all. All the other chems would need to be monitored/adjusted as usual.
I also think its different from the 'liquidator' as it doesn't have a mixing vat of bleach/pool water. When the pool pump turns on (ie: high pressure water flowing through pool returns) venturi pressure pulls bleach out of the storage tank and injects it into the pool return lines. When the pump stops, the bleach just sits in its bleach container.
So I can not view any video at work... And I do not have one of these so I "thought" it used 3 inch tabs like my neighbors does...... total fail.... :)
 

skola28

Active member
Jul 16, 2020
25
Dallas, TX
So I can not view any video at work... And I do not have one of these so I "thought" it used 3 inch tabs like my neighbors does...... total fail.... :)
Ahhh yes! There are systems that use the tablets. This system actually uses liquid chlorine bleach only. Also, I believe the proper septic tablets also do not have stabilizer, although I think there are other complications with using that system on a pool that I'd rather avoid.