Stenner liquid chlorine pump - How to choose and install

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I'd recommend you drill through a coupling or elbow, not just the pipe. The extra thickness of the coupling will give you a much stronger connection. I used a cheap NPT tap to make the threads but with care you can use a brass fitting to form them first, then insert the Stenner injector. Do a practice run first.
 
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I've been running 12.5% bleach in my Stenner for a couple months now. It seems that I get a crystal buildup (salt? calcium?) mainly at the injection point, and it seems to go 1/2-3/4" into the dispensing line, completely blocking flow, and therefore causing the line to pop out of the ferrule at the pump head, flooding the spill area of the tank with bleach.

I called Stenner, and they advised that the only thing I can do to help is to use more dilute bleach, but that would just cause the crystal buildup in the pump tank rather than all in the dispensing line. I suggested going from 1/4" to 3/8" line, cutting an angle of the line at the injection port, using the duckbill check valve even though it's a low-pressure pump, etc., and they said none of those will fix the problem.

I found a product sold in Australia and New Zealand that is supposed to prevent the crystals from forming, but I can't find anyone that sells a similar product in the United States. I looked up the safety data sheet on the Aussie product and found that the active ingredient is < 1% potassium permanganate. I did some quick math and determined I should dose at 0.5 grams per US gallon of 12.5% bleach. I ordered some of the chemical from Amazon and will be trying that tomorrow to see if it helps.

The only other idea I had was to plumb a length of PVC vertically and attach the injection port at the top of that pipe, to create a pressurized air-gap so that the bleach will drop through the air gap in the pipe before hitting the return line to the pool. If the crystals are forming just by reaction to my pool water, should should fix it. I ordered a union, ball valve, clear PVC section, and cap, just in case the potassium permanganate doesn't work. This way I can use the clear PVC on the vertical section to ensure there is an air gap, and I can use the ball valve to stop water pressure from filling the vertical pipe when cleaning/replacing the dispensing line, and I can use the union to drain the water out of the vertical pipe if it fills. But if the crystals are forming from the bleach interacting with the air, this won't fix anything.

Has anyone found that using a more dilute bleach helps prevent the crystals from forming? Or is there any other additive you've found that can help prevent it? I don't care if I have to clear out the crystals, but was hoping for at least 4 weeks between maintenance, instead of 1-2 weeks.

Otherwise it's been great having my FC level automatically dosed 24h and my pool has never been cleaner!

Thanks for any advice you have on the problem!

Update: I added the potassium permanganate last night. It's about 1/4 tsp per 3 gallons. I'll report back in 1-2 weeks when I'm here again and can check the crystal buildup. Hopefully I won't find the line popped off and the top of the tank flooded for once. :)
 
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I use 10% chlorine from Home Depot in my Stenner system, now about 7 years old. I also get deposited solids at the injector but much less frequently than you.

My first failure point was at the duckbill, so I removed it. Then I cut the injector back to remove the restriction. These two steps helped but didn't cure the problem. Now I remove the injector every 6 months and wash it in acid and scrape away the deposits in the PVC "T" fitting. I mounted the injector horizontally to protect it, but now wish it was vertical. I cut back the 1/4" feed line at the injector a couple of inches to remove the deposit restriction. Once a year I replace the entire feed line from the pump to the injector when I also change the pump tube. Every other year I open the Stenner's gearbox and redistribute the grease. Two years ago I had to replace the roller assembly. I also installed a flow indicator for a quick view of system status. At the 5 year point I let my 15 gallon tank go dry in winter and washed out a surprising amount of solids that came with the chlorine. After the first year I went from a number 2 pump tube to a 7 to minimize the run time.

I'm still very happy with my Stenner system and would pick this again over a SWG.
 
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What flow indicator do you use?
I’ll add my 2 cents. I replace my duckbill and the pump tubing every year and clean out the injection point and the “weighted”suction in the tank at the same time.
My T is vertical and I use the 0.51 GPH tube in my EconT and can normally go a year without issues.
When I do have issues is normally because the duckbill turns bad and the pump tube becomes hard. This allows backflow into the tank which in turn dilutes the mix.
 
This is very interesting that you guys don't seem to have as much build-up as me. Do you have plaster pools? I have a fairly high calcium level.

I run my pump continually, at a low feed rate (~3.5 on the variable pump head). I wonder if it would make a difference to run it on a timer at a higher flow rate. I just like that fact that it keeps the chlorine level perfect all day. Algae has always been a huge problem for me. I'm in Texas, so my pool water is very warm in the summer, and I have trees all around the pool that shed a lot of leaves and flowers into the pool 3/4 of the year... always battling phosphates. Ever since setting up the Stenner pump on continuous dosing, my pool has never been cleaner.
 
yottabit said:
This is very interesting that you guys don't seem to have as much build-up as me. Do you have plaster pools? I have a fairly high calcium level.

I run my pump continually, at a low feed rate (~3.5 on the variable pump head). I wonder if it would make a difference to run it on a timer at a higher flow rate. I just like that fact that it keeps the chlorine level perfect all day. Algae has always been a huge problem for me. I'm in Texas, so my pool water is very warm in the summer, and I have trees all around the pool that shed a lot of leaves and flowers into the pool 3/4 of the year... always battling phosphates. Ever since setting up the Stenner pump on continuous dosing, my pool has never been cleaner.
Click to expand...
That may be the reason. I live in PHX, so I know everything about hot pool water :) I only inject once daily and I do it during the cleaning cycle, so lots of flow.
 
In Plano too. We have the leaves and flowers as well. I'm currently dosing 10min @ 0930 and 10min @ 2030, 44.45 oz x 2. I've had to clean the injector point a couple of times and replace the rollers/pump-tube once since installing the Stenner in May of 2019.
 

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yottabit said:
This is very interesting that you guys don't seem to have as much build-up as me. Do you have plaster pools? I have a fairly high calcium level.

I run my pump continually, at a low feed rate (~3.5 on the variable pump head). I wonder if it would make a difference to run it on a timer at a higher flow rate. I just like that fact that it keeps the chlorine level perfect all day. Algae has always been a huge problem for me. I'm in Texas, so my pool water is very warm in the summer, and I have trees all around the pool that shed a lot of leaves and flowers into the pool 3/4 of the year... always battling phosphates. Ever since setting up the Stenner pump on continuous dosing, my pool has never been cleaner.
Click to expand...
Plaster, 30 years old. My CH is 800, fill water is usually 600. Pool temp is 80F now and will max out to about 87 in September. Lots of leaves & flowers all year.

I don't worry about phosphates now that my CYA is in control at 40.

Pump runs every day: 1 hour at high speed, 07:00 for my suction cleaner. Slow speed 1 hour at noon with half of my chlorine dose, 2 hours at 22:00 with the the other half. Our afternoon power costs 53 cents a kWh in the summer, so I keep the pump use to the minimum necessary for great water.
 
Re: the 1/4" female connection to connect the Stenner into the return line. My recently purchased Stenner came with a fitting that has both 1/4" and 1/2" threads. They are 1/4" at the bottom, then it widens to 1/2" towards the middle. Looks like I can just screw it directly into a 1/2" female slip tee - which are commonly available and won't have to drill my own.
 
jolla said:
Re: the 1/4" female connection to connect the Stenner into the return line. My recently purchased Stenner came with a fitting that has both 1/4" and 1/2" threads. They are 1/4" at the bottom, then it widens to 1/2" towards the middle. Looks like I can just screw it directly into a 1/2" female slip tee - which are commonly available and won't have to drill my own.
Click to expand...
that is what I did. :)
 
amin36 said:
" At the point of injection the pressure should be less than 10 PSI"
why is that?
In most cases the pump filter pressure is above 10 psi
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That is the pressure inside the filter housing, not the pressure that is in the hose leading to the pool.
When my pump is running at low speed, the filter pressure is below 5psi, but the flow to the pool is still strong.
 
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I must have been in this thread some time ago, 'cause it popped up. But I've only read the last few posts recently. I don't know anything about Stenner parts, but if you're injecting acid or chlorine into a pool plumbing system, you could consider using something specifically designed for that purpose, and not worry about PSI spec's. This is from a Pentair IntellipH acid injection system. And it also has multiple thread options, including a size that can fit into a 2x3/4x2" tee (might be 2x1/2x2").

I just replaced mine (the acid wears them out) and bought a second one as a spare. Not counting the PVC Tee, the installation took about three minutes, no tools (hand tight). It fits the same supply tube as the part you're looking at: 1/4".

sunplay.com

Pentair Injection Check Valve 522513Z

Pentair Inejction Check Valve for the Pentair IntellipH Controller.
sunplay.com sunplay.com

It doesn't come with the flow gizmo, but I wouldn't use it if it did: just that many more parts and connections to rot in the sun and fail. The only test you need to perform to determine if it's working is the water chemistry test. If you really need to see if it's pumping, you can always just quickly pull the 1/4" tube and see for yourself. That step also tests the integrity of the backflow prevention check valve in the injector. If liquid is coming out of the 1/4" tube, and no liquid is squirting out of the injector (while the filter pump is running) then is-all-good. EZPZ.
 
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