Stenner Dosing Issue

lmartins6746

Member
Jun 6, 2018
13
Simpsonville, SC
Ok, so at the start of pool season (about 6 weeks ago here), I installed my stenner pump to auto dose the chlorine. It is a simple install, it pulls the chlorine out of a 5 gallon bucket buried about 3/4 of the way in the ground. It injects to the return at a level slightly below where the stenner pump is mounted.

It is a variable speed pump that I set to 2.2 gpd and let run for 3:45 minutes (woods digital timer).

So for awhile everything was great. I was able to maintain a constant chlorine level (about 3.5 at the time due to almost no CYA) for weeks on end without adding manually. Then about 2 weeks ago the bucket ran out of chlorine before I added more. After this happened I disconnected the line from the return, set the pump to 10 gpd until it started spitting out chlorine again. I put it back in the return line and left town for a few days.

3 days later I get back the the bucket is almost empty and my chlorine level is ~11 ppm. It should have used less than 1.5 gallons over the 3 days, but instead it dumped ~3 gallons. I turned the pump off for a few days and to let the chlorine level come back down, then tried it again and same thing. Yesterday I measured the chlorine level in the bucket and then again today and I can see that it used about 5 quarts (now set to 2.5 gpd due to bumping CYA back to normal level).


TLDR; My stenner pump is set at about 2.2 gpd and timer to run for 3:45 minutes which should be about .34 gallons a day, but it is instead dosing it about 1 gal per day.

Has anyone seen anything like this? It clicks at the expected interval when running. I figure it is either pumping too much chlorine (gpd) or pumping for too long. The too long is easy to see/measure and I've never seen it running when it shouldn't be (since it would have to run 3x longer than usual I'd think I'd notice). So that makes me think it is the pump. Could this be a pressure/gravity issue that is just now a problem?

Should I maybe setup some tests with and without the pump connected to the pool equipment? I tested the pump before installing (it was used) and it did pump 10 gpd at that setting. It also seemed to have no trouble pumping only 2.2 gpd for about a month.
 

RonsPlc

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May 31, 2015
735
Gaylesville, AL
Just wanted to give this a bump.
I would expect a misbehaving Stenner to UNDER dose, not the other way around.
Maybe @Bama Rambler would be able to help you out here.
 

Bama Rambler

Mod Squad
TFP Expert
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Jun 22, 2009
23,248
SouthWest Alabama
I figure it is either pumping too much chlorine (gpd) or pumping for too long.
By that statement, you've guessed at the only two things that could cause your problem. Those pumps are pretty reliable but something could happen that would make it pump continuously instead of pulsing.

Which model pump do you have?
Assuming you have the dial model, which number is it set on?
Do you see the head pausing at regular intervals when it's running?
Do you know how old the pump is?

Those ratchet mechanisms do wear out over time, but they normally quit running the head instead of running it too much. However, anything is possible.
 

rphpool

Well-known member
Mar 4, 2015
483
Sugar Land , TX
I once had the same issue with my Stenner, so I thought. Came home and FC was at 20ppm. WOW what have I done?
Well it turns out I was changing the timing of my Stenner earlier that week and , well, got the am / pm mixed up. User error on my part.
So I was reading your story and reminded me of my mishap. You said you changed your pump to the 10 gpd to re prime it. Did you remember to change it back to the 2.5 gpd setting? Simple error if you were interrupted during your process. How is it working now at the 2.5 gpd setting?
 

lmartins6746

Member
Jun 6, 2018
13
Simpsonville, SC
I once had the same issue with my Stenner, so I thought. Came home and FC was at 20ppm. WOW what have I done?
Well it turns out I was changing the timing of my Stenner earlier that week and , well, got the am / pm mixed up. User error on my part.
So I was reading your story and reminded me of my mishap. You said you changed your pump to the 10 gpd to re prime it. Did you remember to change it back to the 2.5 gpd setting? Simple error if you were interrupted during your process. How is it working now at the 2.5 gpd setting?
I wish it were that. Definitely was set to 2.2-2.5 ish. Yesterday it was set to 2.5 gpd and it pumped about 5 quarts out the bucket in 3 hrs and 45 mins (12:15 PM to 4 PM) It was not running when I came home and checked it around 7 PM.

I just changed the start time to 2:45 PM to prepare for being gone this weekend (this is where it will work like it supposed to and I'll come back to green pool :))
 

Bama Rambler

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2009
23,248
SouthWest Alabama
At a setting of 2.5 running it 3hr 45min it should pump 0.39 gallons or 50oz.
At a setting of 10 running it 3hr 45min it would pump 1.56 gallons or ~200oz or ~6 quarts.

Either it's running longer than you have it set for (doubtful) or the ratchet system is stuck on full on (Likely).
So here's what I'd do. Set the dial to 10 and adjust the timer to 1 hour run time. That will pump ~50 oz which is about what setting the dial on 2.5 and running the pump 3hr & 45 min should do.
 

lmartins6746

Member
Jun 6, 2018
13
Simpsonville, SC
I ran some tests this past weekend and I think it is a tube sizing issue.

Set at 10gpd it pumped 32oz in about 7-8 mins [~50gpd]
The other tests weren't as exact as the container was empty when I checked it, but I know this:
6 gpd pumped 64 oz in less than 30 mins
2.5 gpd pumped 64 oz in less than 115 mins.

I also learned that it will not pump anything if the pool pump is not running.
 

Steve_in_C

Bronze Supporter
Jul 6, 2017
322
Kinston, NC
A better way to do this is would be to calibrate your Stenner to time required to add 1 ppm to your pool. If you think in ppm, it is easier than thinking of oz / mL etc. PPM/day added is more useful in the long term as bleach concentrations may change.



As long as the Stenner is consistent and pumps the same amount, you should be able to do this with a wide variety of pump tubes / volumes. If your Stenner is pumping much different than it's specs, make sure you have the right voltage. There are many available options for the Stenner motor than our 120VAC standard household AC, including some lower voltage, higher voltage, DC, and AC 50 Hz editions
 

lmartins6746

Member
Jun 6, 2018
13
Simpsonville, SC
A better way to do this is would be to calibrate your Stenner to time required to add 1 ppm to your pool. If you think in ppm, it is easier than thinking of oz / mL etc. PPM/day added is more useful in the long term as bleach concentrations may change.



As long as the Stenner is consistent and pumps the same amount, you should be able to do this with a wide variety of pump tubes / volumes. If your Stenner is pumping much different than it's specs, make sure you have the right voltage. There are many available options for the Stenner motor than our 120VAC standard household AC, including some lower voltage, higher voltage, DC, and AC 50 Hz editions
agreed. I actually made a chart to put out at the pump that gave me the FC for different run times for different chlorine %.
 
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