Which Stenner pump....10 or 22gpd?

anthony21078

Well-known member
Jun 14, 2018
90
Long Island NY
Biting the bullet and purchasing a 15 gallon stenner pump/tank. Last decision to make is GPD sizing which will be either 10 or 22.

My pool is 22000 gallons with a CYA of 40 and I always try to keep my FC on the higher side near 7. I always use 10% bleach with almost a daily ritual of dumping between 80-110 ounces per day. Adding the bleach typically occurs late at night with the pump running and pouring half of the 80-110 oz’s in front of each of the two returns. I certainly don’t do a slow pour but somewhat quickly. I rarely have issues with my water and the chemistry is always correct.

With that said, I figure the larger 22 gpd pump would more closely simulate the way I add bleach and run for a shorter amount of time vs the 10 gpd pump. I’m having a hard time figuring out the math on how long to run the timer so any help is appreciated. Is there any benefit to getting the smaller pump and having it run for longer period of time?
 

anthony21078

Well-known member
Jun 14, 2018
90
Long Island NY
Wow that excel sheet was perfect. Now I'm looking at either a 22 or 50 gpd pump with a 30 gallon tank. Either way, its difficult to find one that is actually in stock on some of these websites.

The 45MFL5 needs 35 to 50 minutes to meet my FC demand.

I found this one with the 45MFL5 but its 3/8" tubing instead of 1/4".......The site says 10gpd but it has to be typo. The part # reflects the 50gpd pump

Rookie question here, is buying the tank and pump separately exactly the same as buying the combo per-assembled system? I'm assuming the pump comes with all the parts I need to attach to the tank right?
 

hexabc

Bronze Supporter
Aug 20, 2017
43
Middletown NJ
Biting the bullet and purchasing a 15 gallon stenner pump/tank. Last decision to make is GPD sizing which will be either 10 or 22.

My pool is 22000 gallons with a CYA of 40 and I always try to keep my FC on the higher side near 7. I always use 10% bleach with almost a daily ritual of dumping between 80-110 ounces per day. Adding the bleach typically occurs late at night with the pump running and pouring half of the 80-110 oz’s in front of each of the two returns. I certainly don’t do a slow pour but somewhat quickly. I rarely have issues with my water and the chemistry is always correct.

With that said, I figure the larger 22 gpd pump would more closely simulate the way I add bleach and run for a shorter amount of time vs the 10 gpd pump. I’m having a hard time figuring out the math on how long to run the timer so any help is appreciated. Is there any benefit to getting the smaller pump and having it run for longer period of time?
My pool is of a similar size as yours. I'm running a fixed head Stenner pump 45MPHP10 (the version for 100psi output pressure) at 10GPD rate. This rate is achieved with tube #2. Switching to 22GPD is as simple as replacing tube #2 with #7, but my setup works great with #2. Here are calculations applicable to tube #2; for tube #7 (22GPD), replace 1280 with 2816:

A simple proportion:
1280 oz (10 gal) - 1440 minutes (24 hours)
desired_chlorine_volume_to add [oz] - pump_run_time/day [minutes]

Hence:
pump_run_time/day [minutes] = desired_chlorine_volume_to add * 1440 / 1280

For example, if your pool needs 80 oz per day:
pump_run_time/day [minutes] = 80 * 1440 / 1280 = 90 minutes.

It is generally a good idea to add chlorine in smaller doses, several times per day. I have an Intermatic P1353 timer, which turns the Stenner pump on at 6am, 11am and 3pm. Make sure that your timer is wired in such a way as to make it impossible tu turn the Stenner when the filter pump is not running.
 
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anthony21078

Well-known member
Jun 14, 2018
90
Long Island NY
My pool is of a similar size as yours. I'm running a fixed head Stenner pump 45MPHP10 (the version for 100psi output pressure) at 10GPD rate. This rate is achieved with tube #2. Switching to 22GPD is as simple as replacing tube #2 with #7, but my setup works great with #2. Here are calculations applicable to tube #2; for tube #7 (22GPD), replace 1280 with 2816:

A simple proportion:
1280 oz (10 gal) - 1440 minutes (24 hours)
desired_chlorine_volume_to add [oz] - pump_run_time/day [minutes]

Hence:
pump_run_time/day [minutes] = desired_chlorine_volume_to add * 1440 / 1280

For example, if your pool needs 80 oz per day:
pump_run_time/day [minutes] = 80 * 1440 / 1280 = 90 minutes.

It is generally a good idea to add chlorine in smaller doses, several times per day. I have an Intermatic P1353 timer, which turns the Stenner pump on at 6am, 11am and 3pm. Make sure that your timer is wired in such a way as to make it impossible tu turn the Stenner when the filter pump is not running.
I understand that pump output is dictated by tube sizing and I found a good price for 50gpd pump for around 160$ new. All other sizes are well over 200$.

This is what I have. If you have a Coke or Pepsi bottling plant near you they throw these out all the time.

30$ + 50$ for shipping is not bad at all. Best price on a stenner 30 gallon tank with shipping I could find is 240$
 

GP2

Active member
Apr 4, 2019
37
Houston, TX
Another stenner calculator that may be helpful here (or links in signature):

The 45MFL5 needs 35 to 50 minutes to meet my FC demand.
Screen shot of output with the 45MFL5 (with spec #5 tube, 50gpd). . . looks to meet 80oz in 18 min, and 35-50min would dose in the 5-7ppm FC range based on 26kgal-10%-50gpd

26k_10pct_45MP5.jpg
 

anthony21078

Well-known member
Jun 14, 2018
90
Long Island NY
I was messing around with the excel last night and changed the bleach to 6%. Left that 6% there today when changing the pump to 50gpd so that's why my numbers were off today. Regardless, a 50gpd pump at 160$ new seems to be the best price I can find. If adding the bleach at this rate seems to be problematic I can always change the hose size.

I have always used 10% bleach but it kept inside in the AC away from light with dates never older then 2 months. Adding 25 gallons or so to a outdoor tank will obviously accelerate breakdown. It wont be in direct sunlight though. Maybe 6% is the way to go now 🤷‍♂️
 

GP2

Active member
Apr 4, 2019
37
Houston, TX
Got it, that runtime makes sense @6%. Yes I think you have plenty of workable options with different bleach concentration or changing tubes once you get up and running and see what setup works best for you. I don’t see any issues even with 50gpm and 10%. I use 12.5% and refill every 3-4 weeks.
 

anthony21078

Well-known member
Jun 14, 2018
90
Long Island NY
Got it, that runtime makes sense @6%. Yes I think you have plenty of workable options with different bleach concentration or changing tubes once you get up and running and see what setup works best for you. I don’t see any issues even with 50gpm and 10%. I use 12.5% and refill every 3-4 weeks.
12.5% for almost a month huh? Hmmmm, when you test FC as it nears 3 to 4 weeks since the last tank fill-up, are you noticing FC levels are the same as week 1? Do you need to run the pump and any longer towards the end of the refill cycle to account for degraded bleach?
 

GP2

Active member
Apr 4, 2019
37
Houston, TX
12.5% for almost a month huh? Hmmmm, when you test FC as it nears 3 to 4 weeks since the last tank fill-up, are you noticing FC levels are the same as week 1?
I’ve only been running the stenner for 6weeks or so and the fist month short-filled the tank twice so was more like 2 weeks storage with no issues. Stretching for 3-4 now... I’m going into third week and still seeing no change in FC vs runtime. Will be keeping an eye on it over the next 10 days or so to see if any impacts. It will likely be 21-26 days max and I’ll need a refill.
 

Chasarms

Silver Supporter
May 8, 2020
344
Dardenne Prairie, MO
No matter what pump you choose, don’t simply expect it to pump at exactly the published rate. Set up your system and have it pump into a measured container so you can calculate the actual pump rate. My Stenner was published to pump .75 ounces per minute, but testing revealed that it pumps about .95 ounces per minute. That’s a big swing. It doesn’t impact its usefulness, but it changes the run times significantly.
 

anthony21078

Well-known member
Jun 14, 2018
90
Long Island NY
No matter what pump you choose, don’t simply expect it to pump at exactly the published rate. Set up your system and have it pump into a measured container so you can calculate the actual pump rate. My Stenner was published to pump .75 ounces per minute, but testing revealed that it pumps about .95 ounces per minute. That’s a big swing. It doesn’t impact its usefulness, but it changes the run times significantly.
Good advice 👍

On another note, what causes bleech to breakdown quicker......sunlight or heat?

I have a shed that is approximately 10 feet away from my equipment pad. I have the option of placing the tank inside the shed which is always dark but also 10-15 degrees warmer then the outside air temperature.
 

Chasarms

Silver Supporter
May 8, 2020
344
Dardenne Prairie, MO
I am on week three of dosing with the Stenner. Between testing and dosing, there’s chlorine in my tank that is nearly a month old. It has sat in mostly shade n temps as high as mid 90s. So far, I have not noticed dropping chlorine levels. I have been tweaking the run times trying to find the sweet spot, and tests seem to reflect the ppm I am expecting.

My tank is a 13 gallon heavy duty plastic barrel. I bought it in FB marketplace for $8.
 

BowserB

Silver Supporter
Jul 29, 2018
327
Katy, Texas
Related question. I keep reading that higher concentrated chlorine degrades faster than lower. For now, I'll accept that as fact. Now, since 12.5% chlorine is 87.5% water, if your bought 12.5% and diluted it 50% with water when you fill the tank, would it's storage life be comparable to filling the tank with 6% chlorine? I'm thinking of less chlorine solution to transport, plus in my shopping I find higher concentrate chlorine to be effectively cheaper often than lower concentrate. Should the dilution be with distilled water?
 

DanF

Silver Supporter
Mar 17, 2019
187
Chandler, AZ
That is what is suggested for acid to dilute 50:50, it will also work for Chlorine. It will need longer runtimes but will be more precise.
Why the increased precision? Is it because you can rely on the lower strength percentage being more accurate over time?
Related question. I keep reading that higher concentrated chlorine degrades faster than lower...Should the dilution be with distilled water?
I've read the same, but I can't find it right now. As far as distilled water I have also read (and can't find right now) that distilled water is preferable for Cl dilution because tap water may contain metal;s which will react with the chlorine. If true, means more jugs to lug.
 

Flying Tivo

Well-known member
Jan 24, 2017
1,884
Monterrey, NL, Mexico
Timers usually dont have seconds only minutes of additions, the lower the strength more minutes to run. You are looking way to much into it. This systems works, little more or less of additions wont make your levels go critical. Regular tap water is ok unless its well water with known metals.