Potential Issue with a Stenner Pump Set Up and Entended Spa Use?

[JasonO]

Hi Everyone,
We are just finalizing our build, and going to pull our permit. The 3am wake up questions are coming fast and steady now!

So far, with help from this forum, I'm gaining a lot of confidence about the plan. I've decided to go with a Stenner pump for our new 50k gallon pool build. Its going to take a lot of chlorine, but I can get the high test stuff here in 5 gallon sizes, and I'm building a handy shelf to put it on while siphoning to the tank. It shouldn't be too much of a chore. I'm a geek about systems, and like the idea of starting my pool with incremental dosing of everything. Down the road, I can always go to a SWG, I'm plumbing for that option, and the salt content will be slowly rising anyway. We are going to run our water features a lot, so I might even add another pump for acid, if it becomes worthwhile.

Everything will be automated with the Omnilogic program. Filter, Stenner pump, solar, lights, waterfalls, etc. I will take daily test readings, chart them, and slowly adjust to my automation program. Hopefully I'll end up with some decent baseline "programs" and then adjust things as conditions dictate. A-OK so far.

I'm going to use the fixed output Stenner pump, and control dosage with a time clock schedule. My plan, is to dose the pool with about 75% of the necessary chlorine in the afternoon/evening, so that it has maximum effectiveness overnight, and then put in the other 25%, during the late morning, to help it maintain FC through the heat of the day. Good plan? I have no idea, but experimenting and learning is the fun part.

So far, so good. Then last night, this occurred to me:

What if we are enjoying the spa all afternoon/evening? Friends stop by on a Saturday, liquid refreshment flows abundant, and we end up using the spa from say, 4pm until midnight? This is a likely scenario! Now, if I don't remember to alter the program, won't I be dumping a huge load of chlorine into just the spa?

My knowledge of pool systems is limited to the pool I grew up with, but when we turned on the spa and heated it, we turned off the filtration to the pool, and essentially created a closed loop system to the spa.

Playing with the Pool Math calculator, and some very general assumptions, I could be using 120 oz of 12% chlorine per day in the summer. 75% of that (my planned evening dose) is 90 oz. In a 1500 gallon spa (guessing on size here), that would raise the FC by 59 ppm. That seems pretty aggressive, even with a bunch of bodies in there.

Am I understanding the process right? Is this as concerning as it seems to me?

Do I need to turn off my Stenner pump, if we are going to be using the spa during the dosing period? Or maybe change the program to spread the dosing our over maybe 4 periods, so I never put in more than 30 oz at a time? Would that still be problematic?

Or do the modern pool systems have separate loops, so that the pool and spa both circulate independently regardless of use? I can ask my PB about this, but since I am taking control of the build specs, I prefer to sound at least halfway knowledgeable about these things.

If anyone can enlighten me, I would sure appreciate it!

Jason

 

[Bama Rambler]

Since you're using automation to run the injection pump. Program it so that it only injects when in pool mode and the pump is running. I think the Omnilogic will do that.

You can also put the injection point in a line that goes to the pool only.

 

[JasonO]

Thank you Bama. Of course. The injection point would never be before the diversion valve to the spa, would it? Duh! I'm getting wrapped around the axle on the details, and missing the obvious. I better ask the PB for a plumbing plan.

I hope that is the case with the Omnilogic. Looking at Hayward's videos and literature, it looked like those features might only available running Hayward equipment. If I can program any of the relays with those run/don't run parameters, then there wouldn't be any issue at all. I will ask about that as well.

Thanks again, I better work on something else for a while...

 

[Jimrahbe]

Jason,

I'm not sure that your plan to add 120 oz. of bleach during the summer months will be enough.

Most pools use between 2 to 4 ppm per day in the summer and I believe that you will be on the high end being in California.. So I would plan on using 200 oz. or more each day.

That is a lot of bleach even if you can buy it in 5 gallon cans.

I believe that you would be better off installing a Salt Water system and then using your Stenner to just supplement the extra chlorine that you need.

This would mean that you would need less bleach and most likely none is some parts of the year. When using the Spa your automation system would automatically reduce the chlorine output of the SWCG.

This would give you the best of both worlds (Stenner and SWCG).

With such a large pool, you would still have to run your SWCG at 100%...

Thanks,

Jim R.

 

[JasonO]

Thanks Jim,
I appreciate the heads up on the bleach quantities. I will investigate some more.

I also agree 100% that a SWG is the best solution . That's what we will end up with. But I'm stuck right now. I really don't know how large of a system I will need, but it's larger than the standard residential offerings. Two SWG systems? One commercial size unit? Controls? Warranty? Its a lot to research. It's likely to be a $6-$10k solution as installed by my PB. I don't want to guess wrong. That's a lot of other backyard improvements in that outlay.

Also, my PB is salt-resistant, so I'm going to be fighting that battle. And, we desperately need to finalize our plans so we can get started. We have three separate permits to pull to get our yard/pool/cabana approved, and need to get them going concurrently.

So a Stenner pump seems like the right solution. Probably $500 to get started, and it can handle any size load. After a year of lugging lots of bleach, I should have a pretty good handle on our requirements, will be familiar with our controls. I can take my time selecting the right SWG solution, based on real life data. Meanwhile the salt content will be rising anyway (albeit minimally), and the Stenner will still be a useful part of the future system as my supplementary chlorine source.

My PB will plumb for future expansion, and I've tried to spec everything as if it were a salt system, so hopefully it won't be too painful to add later. And it allows us to get going now.

Is that a misguided plan? I think it makes the most sense for our situation. All opinions welcome!

Jason

 

[Jimrahbe]

Thanks Jim,
I appreciate the heads up on the bleach quantities. I will investigate some more.

I also agree 100% that a SWG is the best solution . That's what we will end up with. But I'm stuck right now. I really don't know how large of a system I will need, but it's larger than the standard residential offerings. Two SWG systems? One commercial size unit? Controls? Warranty? Its a lot to research. It's likely to be a $6-$10k solution as installed by my PB. I don't want to guess wrong. That's a lot of other backyard improvements in that outlay.

Also, my PB is salt-resistant, so I'm going to be fighting that battle. And, we desperately need to finalize our plans so we can get started. We have three separate permits to pull to get our yard/pool/cabana approved, and need to get them going concurrently.

So a Stenner pump seems like the right solution. Probably $500 to get started, and it can handle any size load. After a year of lugging lots of bleach, I should have a pretty good handle on our requirements, will be familiar with our controls. I can take my time selecting the right SWG solution, based on real life data. Meanwhile the salt content will be rising anyway (albeit minimally), and the Stenner will still be a useful part of the future system as my supplementary chlorine source.

My PB will plumb for future expansion, and I've tried to spec everything as if it were a salt system, so hopefully it won't be too painful to add later. And it allows us to get going now.

Is that a misguided plan? I think it makes the most sense for our situation. All opinions welcome!

Jason

Jason,

Sounds like a good plan to me...

Thanks for the feedback..

Jim R.

 

[cfherrman]

Ist the point of clorine injection systems is to inject small amount of clorine throughout the day and/or night?

 

[bmoreswim]

It is an aspect but not the point. The point is to chlorinate without adding CYA.

 

[cfherrman]

I was speaking about just only running injection at night rather than having it run throughout the day

 

[Backyard_Lap_Pool]

We have one 1.5” return line plumbed to the spa with a check valve off of the pool manifold. This creates positive flow when the system is in pool configuration - making the spa flow over its infinity edge back into pool. This is also the configuration in which chlorine is dosed into pool, so late at night when the chlorine pump kicks on, the spa gets its portion of the chlorine... and the chlorinated pool water cycles through the spa the remainder of the day as the water circulated through the combined manifold. When the spa is isolated during heated operation is when the chlorine levels would theoretically drop. That being said, we don’t keep it in spa mode for more than a few hours at a time so it isn’t a big worry. Bottom line: when ever it is in pool mode, the spa gets chemicals.