SmarterSpa cell placement question

[DrNinjaman]

I just took delivery of my spa this July, and we love it. I'm converting to a salt water tub with a SmarterSpa SWG. When I was first looking into the SmarterSpa, the inline kit seemed very appealing, as my tub has a circulation pump that runs all the time, so should work for the inline install just fine. However, since the spa is so new, it's still in warranty and
I didn't want to mess with anything in the cabinet until that runs out. Hence, I have a drop in cell for the time being. Once the cell needs replacement, the warranty should have expired, so I can convert to inline at that time.

Meanwhile, dropping the cell over the side is fine, but given the size of my tub, the cell run time may end up needing to be quite a long time, so I'd like to figure out a way to be able to leave it in the water while we use it. It fits in the filter area, but that seems not ideal since the water's not that deep. However, I did notice that one of my filters has the cap and hole in the middle for installing a Nature2 mineral stick, which I do not have. That hole fits the OD of the salt cell perfectly, so I can stuff the cell into the middle of the filter and it seals into the bottom of the filter opening leading to the circ pump. Then the hole in the end of the cell becomes the only path for water to flow. The upper end of the cell seals to the top of the filter body, preserving the filtering action. It's like it was designed to go here. Do you think the flow rate through the cell in this location will be adequate to draw the chlorine down into the system against buoyancy without being faster than what the cell can handle? Or am I just creating a chlorine trap that's going to degrade my cell body and filter faster than necessary, as well as not sense the correct chlorine levels in the spa water?

The inline kit installs the cell pointed up, so the bubbles rise in the same direction as the water flow and the chlorine sensor is at the bottom where it won't see any effect from its own chlorine production until it has mixed through the whole tub. That is obviously the better orientation, but putting it in the filter would be nice if it works okay in the meantime. I might test it a bit to see how it compares once I have the levels set for the typical operation.

 

[duganderson]

I regret I don't have an informed opinion about the inline installation.

One option, however, is just to pull it out briefly when you use it. I do that and many others do too. I've heard that taking it out does not do anything problematic and I think it is designed to automatically shut off when you pull it out.

 

[DrNinjaman]

I regret I don't have an informed opinion about the inline installation.

One option, however, is just to pull it out briefly when you use it. I do that and many others do too. I've heard that taking it out does not do anything problematic and I think it is designed to automatically shut off when you pull it out.

Yeah, that's certainly an option, but I'd rather not disrupt the cycle once I get this thing dialed in, you know? I'll play around with it and see what happens. Messing with stuff keeps me busy. Oh, one other thing, do you know what the lowest water temperature these things will run at is? Just in case the winter electric bills threaten to ruin Christmas and I have to turn it down later in the year. I asked Controlomatic, but I don't think they're returning my emails anymore after I gave them such a hard time about how dumb it is to have an indoor rated power supply for a device that will often be used on outdoor spas. Also their manual is fairly contradictory in this regard. I mean I bought this thing to have less to worry about regarding maintaining the spa, not more.

 

[duganderson]

I don't know about lowest water temperature. My guess is that it would work at any temp.

For the power supply, for my setup, it's easy to run an extension cord into the heater/pump area and put the power supply there. I've heard other people install a 110v pig tail off of their control box and plug in the power supply there. What are you thinking of doing?

 

[DrNinjaman]

I don't know about lowest water temperature. My guess is that it would work at any temp.

For the power supply, for my setup, it's easy to run an extension cord into the heater/pump area and put the power supply there. I've heard other people install a 110v pig tail off of their control box and plug in the power supply there. What are you thinking of doing?

The spa is close enough to the back of my house that the power cord can reach into the house and plug into an internal GFCI protected outlet, so I'm going to run a piece of conduit through the wall and seal it up. I've seen other mentions about running a pigtail off the circ. pump power supply and leaving it inside the skirt, and I'll probably do that eventually since that would make sense for an inline install so the chlorine isn't generating when the pump is off. But until the tub is out of warranty, I'd rather not mess with anything inside the cabinet.

Based on other threads in this forum, I think there is a lower water temp where the cell won't make chlorine efficiently, I just don't remember where I saw it and what that temp is.

 

[DrNinjaman]

Okay, so a quick search later and I have found my answer: depending on brand, most shut off between 50 - 60 F. However, I think this may be more of a strategy to save the cell rather than a hard lower limit on when the cell will function, as bacteria and algae growth below 50F is very depressed. Good to know.

 

[Mdragger88]

Yeah, that's certainly an option, but I'd rather not disrupt the cycle once I get this thing dialed in, you know? I'll play around with it and see what happens. Messing with stuff keeps me busy. Oh, one other thing, do you know what the lowest water temperature these things will run at is? Just in case the winter electric bills threaten to ruin Christmas and I have to turn it down later in the year. I asked Controlomatic, but I don't think they're returning my emails anymore after I gave them such a hard time about how dumb it is to have an indoor rated power supply for a device that will often be used on outdoor spas. Also their manual is fairly contradictory in this regard. I mean I bought this thing to have less to worry about regarding maintaining the spa, not more.

My spa temp won’t go lower than the 80’s unless I unplug it - obviously your mileage may vary. Just lowering the temp even a few degrees offers savings especially if you know u won’t be using the tub for a while.
Fwiw- I don’t remove my drape over cell when soaking. I guess i like to live dangerously its not like i mess with it while its on or anything either. My kids also know not to mess with it.
If your pump runs all the time it will probably be fine for it to go where the mineral stick would go. You could try it & monitor the filter for increased degradation - also take a fc sample from the area to determine if high fc levels are present.

 

[DrNinjaman]

My spa temp won’t go lower than the 80’s unless I unplug it - obviously your mileage may vary. Just lowering the temp even a few degrees offers savings especially if you know u won’t be using the tub for a while.
Fwiw- I don’t remove my drape over cell when soaking. I guess i like to live dangerously its not like i mess with it while its on or anything either. My kids also know not to mess with it.
If your pump runs all the time it will probably be fine for it to go where the mineral stick would go. You could try it & monitor the filter for increased degradation - also take a fc sample from the area to determine if high fc levels are present.

Yeah, taking a sample specifically from inside the filter after it finishes a run is a good idea. I'll do that after I get it dialed in on zero point and run time with it in the usual place
This tub has a low power mode that can take the water temp down really low, though obviously I'd like to keep it reasonably warm most of the time so we can use it without having to start warming it up the day before. It is going to depend a lot on how the power bills look though. Maintaining it at 100 all the time as the weather has gotten colder spiked the bills up pretty quick though.

 

[DrNinjaman]

I've put the cell into the filter again. The sensor in it seems to read the water better in a flow rather than the slower moving water in the bottom of the tub. I think the chlorine dissolves into the water better too, since it is in contact with the water through the length of the return plumbing, circ pump, heater core, and then out into the center of the tub. If it degrades the filter faster, I think I will just live with it.