Saltron mini and hot tub Chlorine management

monoptn

Bronze Supporter
Dec 7, 2019
21
Clarksville, TN
Greetings. I am new to the forum, and new to the world of spa and pool ownership (about 3 weeks or so in on the pool, a week on the tub). TFP has been a godsend and I have had great success balancing and running my pool and tub. The app tells me what I need to do, I do it, and the results show. Now, I am starting to look for the "easy button" on the hot tub.

My hot tub is 425 gallons, and I am using a Saltron mini to help manage the chlorine. I've been testing multiple times per day to get a handle on what happens after use and how to bring it back in balance, etc. I have read the chemical guide on TFP How do I use Chlorine in my Spa (or pool)?. At this point, I am working toward a routine, and hope that someone here has one down that might serve as a rough guide for me.

My thought process is that I can figure out how many hours per day of run-time of the Saltron will MAINTAIN a given level of chlorine, then after use, I should ADD the estimated amount of free chlorine that I used up. The guide that I mentioned above indicates that you might expect to use 7ppm/hour per person in the tub (less gallons than mine as I recall). And that seems to be fairly accurate for what I am seeing. How many hours per day should I start at to maintain my chlorine level?

Is it reasonable to think that I can test the tub just before I can get in, dump in an estimate of bleach when I get out, drop the mini in, and be ready to go the next day? If I use the tub every day, is it reasonable to think I could get out of the tub, drop in the Saltron (set to a higher number of hours), and have the Saltron bring the FC back to where it needs to be for the next day and NOT add bleach when exiting? THAT would be super easy.

What are your best ideas for managing a tub using the Saltron? I am eager to hear your ideas TFP!

Thanks!
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
15,326
Bedford, TX
M,

Your plan sounds ok to me.. Just remember that you will need to open the lid for an hour, 2 or 3 times a week to allow the CC's to burn off.

I have the mini, but a smaller 200 gal spa that I use almost every day and I almost never add any liquid chlorine. But... I only use it for about half an hour at a time. Sometime the wife and I, but generally just me. I add the cell after I am done and it runs for 5 or 6 hours. I usually only test about once a week, during my normal pool maintenance. I do not try to keep a low level of FC... I try to have enough FC when I start so that it never drops below my minimum before I get out.. If I do this, then it will be fine the next day before I get in. There is no downside to have too much FC as long as you stay below the SLAM level.

You are supposed to take a shower before getting in the spa, but I never do and don't know anyone that does. This causes oils and such to build up that all the chlorine in the world will not remove and so you still have to change the water every 3 to 4 months.

Thanks,

Jim R.
 

jseyfert3

Bronze Supporter
Oct 20, 2017
477
South-Central WI
I don't (yet) have one, but from what I've seen, it is reasonable to use only the Saltron (usually), at least if you have a regular usage schedule. Key being regular, like every day or every other day, otherwise I would imagine the chlorine would get too high when it doesn't have bather waste to deal with.

The Saltron Mini puts out up to 1.1 oz of chlorine (gas) per day. Using PoolMath you can see that for your 425 gallon spa, this would be 19 ppm of FC per day. If you have determined that 7 ppm/person/hour is what you need (this is highly dependant on the people due to showing/temps/size of spa/etc), then you'd need almost 9 hours of runtime per person per hour on the Mini to generate enough chlorine. So two people for an hour every day and you'd need 18 hours of runtime just to deal with the bather waste, plus the normal amount for maintenance.

When we get a Saltron Mini it's be nice to use only that, but with our sporadic schedules I'm not sure it would work too well. I think we may have to set it for maintenance levels for periods of non-use, and just add however many ounces of bleach after each use.

Reading your post made me wonder about hacking the controls though. With an Arduino or Raspberry Pi, you could almost certainly modify the controls such that it outputted only enough hours per day to maintain FC when not in use, with a manual override to run for x hours after usage to get rid of bather waste. That would really handy for sporadic usage schedules...
 

mrwoo

Well-known member
Nov 9, 2019
54
kalispell, mt
I bought a smart outdoor outlet for mine. I was running it 24/7 because something was consuming my FC. I would have to add about 4oz of bleach after a couple hours use. If I did not use it for a day or two then the saltron would go above my slam level (which was 12). I am currently draining my tub after the ahh-some calcium stearate purge @JoyfulNoise pointed me to.

Providing my issues are resolved, I plan on using my outlet and then using the app or alexa to manage it as needed, perhaps creating numerous time schedules depending on my routine. That's better to me than a simple 24 hour timer.

The best confirmation that I've learned something here and am doing something correct is that my daughter brought a guy home who has never been in the tub and has super sensitive skin that gets really dry. He did not notice my water drying him out, etc. She then took him to a really expensive spa after skiing and he messaged me while he was in that tub saying he could not believe how much more harsh that tub was. It was not a salt water tub and is maintained pretty well as it's swanky. I thought I noticed the salt water being smoother but wasn't sure till that point if it was. Even if I have to add a slug of bleach I like the feel of it. Just sayin :)
 

jseyfert3

Bronze Supporter
Oct 20, 2017
477
South-Central WI
The best confirmation that I've learned something here and am doing something correct is that my daughter brought a guy home who has never been in the tub and has super sensitive skin that gets really dry. He did not notice my water drying him out, etc. She then took him to a really expensive spa after skiing and he messaged me while he was in that tub saying he could not believe how much more harsh that tub was. It was not a salt water tub and is maintained pretty well as it's swanky. I thought I noticed the salt water being smoother but wasn't sure till that point if it was. Even if I have to add a slug of bleach I like the feel of it. Just sayin :)
My guess is the lack of skin drying has more to do with the harshness of the FC being reduced do to CYA usage and less to do with the salt. This is why CYA is recommended here at TFP for covered/indoor spas even though it's not required for preventing FC breakdown due to UV (which is the primary reason to use CYA in an outdoor pool).

Most health agencies ban the usage of any amount of CYA in public pools due to a lack of understanding the science of the FC/CYA relationship, and so even though they are maintained at only 1-2 ppm of FC, the FC in commercial pools/spas is way more harsh than even SLAM levels of FC in a pool/spa maintained according to the FC/CYA chart that TFP uses.

It's funny but sad, actually. On one hand most health agencies ban all CYA in commercial pools since it can make FC less effective if there's too much of it. On the other hand a ton of private pools end up with algea and other issues (like cloudy water or lack of sanitation) due to pool industry "guidelines" and "practices" leading to too much usage of stabilized chlorine, especially reliance on trichlor, which leads to excessive CYA buildup. Clearly there is a better way, something in-between these two extremes...oh yeah, it's TFP! :D

What's funny is the pool industry sort of gets it. My Taylor handbook that came with my K-2006 test kit did mention that too much CYA can lead to ineffective FC...but they didn't mention how much was "too much" and touted the benefits of stabilized chlorine (trichlor and dichlor) way too much. Stabilized chlorine does have it's place, but that place is supplemental usage, like adding when more CYA is needed, or trichlor pucks in floaters/feeders for a vacation if you don't have a SWCG, not everyday usage.

Luckily chem geek is out there trying to get the industry on board with the whole FC/CYA relationship (plus other aspecs of pool chemistry like arbitrary TA requirements that are expensive/hard to maintain) , so hopefully in time even public pools will come to understand and properly use CYA, but government/industry backed guidelines take a lot of time and effort to change...
 

monoptn

Bronze Supporter
Dec 7, 2019
21
Clarksville, TN
All good comments and remarks. It sounds like I am on the right track. It would be nice if the mini had a "super-chlorinate" or similar setting where you could have it add a dollop of chlorine after use, then revert to the maintenance schedule. My kids used it last night and when I checked this morning it was at about 4fc. I just used it for 15 min, and afterwards, the chlorine had not budged....I guess I was really clean! I dumped an Oz of 10% bleach in when I got out, and my son was about to get in. I'm gonna see how it does today with that and the mini being in the water when not in use for 14 hours on the setting. The water is clear and I have Free Chlorine, so hopefully I will live.
 

jseyfert3

Bronze Supporter
Oct 20, 2017
477
South-Central WI
I just used it for 15 min, and afterwards, the chlorine had not budged....I guess I was really clean!
Note that not all waste will result in immediate chlorine usage. I've personally seen FC dropping faster than no-use "standby" rates for up to a couple days after usage, indicated waste is still being oxidized. I would hazard a guess (I'm not good at chemistry) that this is stuff like oil that takes longer to break down.
 

monoptn

Bronze Supporter
Dec 7, 2019
21
Clarksville, TN
Ok, here's another one for y'all. This morning my tub was at about 7-8ppm FC and my CYA is 50 ( I errantly stated 30-40 earlier....it's actually 50, a little high I know). My kids used it for a few hours during the day and when I checked it again it the FC was at zero, but the water was clear. I dumped 6oz of 10% bleach, expecting that would bump it up to 11, but instead it bumped the FC to 18.5. Apparently my bleach is stronger than 10%, my tub holds less than 425 gallons, or possibly a combination of both. (the bleach is Kem-tek from Lowes, and the instructions on the bottle indicate that 13oz per 10,000 gal will raise the FC 1ppm, which works out to a 10% bleach according to poolmath app). The CYA addition and the muriatic addition seem to have more impact than expected too, so I think I am going to knock my tub volume down to about 380 gal in the poolmath app to account for this. I've checked my measurements and I am certain that I am accurate, or very close, on the bleach volume I am adding. Is there anything I could be overlooking?

And the final question, if you find your tub has hit zero FC as mine did today, but the water looks and smells good, would you just bump it back up to normal FC and use it right away, or undergo a SLAM and OCLT, or at least a shock, as recommended in the hot tub chemical guide?

Thanks!
 

jseyfert3

Bronze Supporter
Oct 20, 2017
477
South-Central WI
The couple occasions I've accidentally run my FC to zero I take it up to the SLAM level but don't actually SLAM, and just monitor chlorine level a bit better next time.

Usually it was because we didn't use it for a number of days and I forgot to check the level. A SWCG will certainly help me in that regard.
 
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Backcountryski

Well-known member
Aug 31, 2019
46
WA
I use my SWG to keep my chlorine at a base level, then add liqiud based on how many bathers and how long they were in the tub. Seems to be the easiest way for me, rather than trying to chase the chlorine level with the SWG all the time. I test prior to getting in, and then I have a decent idea what I need to add when I get out (based on expierence and lots of testing), so now I do not test, I just throw in bleach and go about my business. Yes, when my girls have used the tub (with friends over) they have run it to zero. I just add bleach to a shock level and call it good and have not had any issues.
 
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monoptn

Bronze Supporter
Dec 7, 2019
21
Clarksville, TN
I use my SWG to keep my chlorine at a base level, then add liqiud based on how many bathers and how long they were in the tub. Seems to be the easiest way for me, rather than trying to chase the chlorine level with the SWG all the time. I test prior to getting in, and then I have a decent idea what I need to add when I get out (based on expierence and lots of testing), so now I do not test, I just throw in bleach and go about my business. Yes, when my girls have used the tub (with friends over) they have run it to zero. I just add bleach to a shock level and call it good and have not had any issues.
That is the track I am on now. Getting a handle on everything and teaching the kids to dump X oz. of chlorine in based on how long/how many of them are in, then I let the SWG maintain it. The other night after I want to bed my kids invited some folks over and had a hot tub party of 7. The next day chlorine was virtually zero and I had to close if for a couple of days as the water got a little cloudy and foamy, and my CC was about 3-4. But after maintaining FC of around 20 for a day then let it taper back down, it all cleared up. I did add some MPS, and have been adding a tablespoon of that after each soak also. It really seems to help. Water is crystal clear again. My CYA is a bit high - about 50 - but I am just going to let it taper down as I have to add water due to splashouts/degradation. At worst, I'll live with it at 50 until I drain and refill, I just have to maintain a bit higher FC level.

May I ask, how many gallons is your tub, and how many hours/day does your Saltron run to maintain (if it is indeed a Saltron).
 

Backcountryski

Well-known member
Aug 31, 2019
46
WA
That is the track I am on now. Getting a handle on everything and teaching the kids to dump X oz. of chlorine in based on how long/how many of them are in, then I let the SWG maintain it. The other night after I want to bed my kids invited some folks over and had a hot tub party of 7. The next day chlorine was virtually zero and I had to close if for a couple of days as the water got a little cloudy and foamy, and my CC was about 3-4. But after maintaining FC of around 20 for a day then let it taper back down, it all cleared up. I did add some MPS, and have been adding a tablespoon of that after each soak also. It really seems to help. Water is crystal clear again. My CYA is a bit high - about 50 - but I am just going to let it taper down as I have to add water due to splashouts/degradation. At worst, I'll live with it at 50 until I drain and refill, I just have to maintain a bit higher FC level.

May I ask, how many gallons is your tub, and how many hours/day does your Saltron run to maintain (if it is indeed a Saltron).
My tub is 330 gallons. My SWG is a bit different, it is part of the tub itself and has a setting from 1-10, I have found that 6 seems to keep it where I want it, although I did an ahh-some purge yesterday so I am curious if it will be able to run a little bit lower as I got quite a bit of gunk out which I am sure was chewing through some chlorine. I have found too, after the kids have friends over (and have the same scenerio as you), that cleaning the filters helps get things back in check as well especially the foaming.
 

monoptn

Bronze Supporter
Dec 7, 2019
21
Clarksville, TN
My tub is 330 gallons. My SWG is a bit different, it is part of the tub itself and has a setting from 1-10, I have found that 6 seems to keep it where I want it, although I did an ahh-some purge yesterday so I am curious if it will be able to run a little bit lower as I got quite a bit of gunk out which I am sure was chewing through some chlorine. I have found too, after the kids have friends over (and have the same scenerio as you), that cleaning the filters helps get things back in check as well especially the foaming.
Yep, I swapped a fresh filter in as well. All good now!
 
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monoptn

Bronze Supporter
Dec 7, 2019
21
Clarksville, TN
Oh yea, and then there is this....I have only used MPS a couple of times when I felt like I really needed it, but honestly I think just giving a hit of chlorine works as well and doesnt mess with your testing.
Yeah, I wasn't using MPS at the time. Is it foolhardy to think that I can skip testing CC if I have adequate FC, no foam, clear water, and FC usage rates that are not excessive?
 

Backcountryski

Well-known member
Aug 31, 2019
46
WA
Yeah, I wasn't using MPS at the time. Is it foolhardy to think that I can skip testing CC if I have adequate FC, no foam, clear water, and FC usage rates that are not excessive?
I don't think it's foolhardy, but others may disagree with me. I do use CC's to know when it is time to change the water though, so there is that. If you do it on a set schedule, like every 4 months or so, it is probably not an issue....It just takes away one data point that you can use to know what is going on with your water. If you are ok with that, then go for it. I also read somewhere that SWG do not really like MPS. It is ok once in a while but not good to use all the time. Perhaps someone smarter than I will chime in why...I have moved away from MPS with the exception of my daughters having a pool party or something, then I use it "just because" it makes me feel better. I honestly believe just adding in more bleach does just as well.
 
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