Does anyone have a suggestion for a good salt water generator for my hot tub? Do they work as good as a pool swg?
salt water chlorinator
- Thread starter ethany
- Start date
TechniChlor and related products from ControlOMatic have been mentioned on this and other forums. They basically seem to work as advertised. Just remember that the chlorine demand fluctuates a lot from bather load so if you don't use the spa regularly then you may still need to add chlorine after your soak since the boost mode may not be enough (or fast enough).
Why do u need to add chlorine if not used often?As far as bather load it will only be my wife and I. Is it much different from a pool swg. I have one for my pool and it's pretty much maintenance free.
One of the reasons for the swg is we hate the bromine smell.
One of the reasons for the swg is we hate the bromine smell.
elwood58
LifeTime Supporter
ethany said:
You will need to set the chlorine production rate fairly low, as you will have limited sun exposure, and very few biologicals to deal with unless using the tub. If you over produce, it will accumulate, even with the high heat. It is best to keep it fairly low, and add a few ounces of liquid chlorine when you get out from a soak.
If you are soaking every day, you may get away with cranking it up a bit. Just do regular testing when you start out.
elwood58
LifeTime Supporter
The range for a covered spa is probably 1-3 ppm. For an SWG it is 1 minimum. This is with zero CYA. I would shoot for keeping it at 2 ppm minimum.
If you are the disciplined type, you should be OK. If you are the ignore for several days type, get it to 3 ppm for a while.
If you are the disciplined type, you should be OK. If you are the ignore for several days type, get it to 3 ppm for a while.
You may find the chlorine to be too strong and to smell too much if you don't have any CYA in the water. If you do end up using CYA, then put in around 30 ppm and target about 2 ppm FC for the start of your soak and dose higher after the soak. Even at hot spa temps, this should be a significantly lower active chlorine level so less oxidizing to your swimsuits and skin and should outgas less so should smell less. One way to build up your CYA level is to use Dichlor instead of bleach after some of your soaks -- cumulatively 33 ppm FC would give you 30 ppm CYA though obviously not all at once.
How often do I need to test the water? I know with my pool n swg once I get it balanced I test once a week. Unless we get long heat waves or a lot of rain. Along with the bad smell of bromine I am considering a swg for less maintenance. Thanks
If your spa usage is very regular in terms of number of people and how long you soak, then you may find that your chlorine usage is consistent. However, until that point in time you should test before each soak to ensure you've got 2 ppm FC or so. Also, just because you'll have a saltwater chlorine generator doesn't mean you'll be able to avoid adding chlorine after your soak. The "boost" mode may not be enough to oxidize your bather waste. Also, if you only use the spa once or twice a week, then you'll want to set the saltwater chlorine generator to a low level to maintain a background level of chlorine so that you start your soak with around 2 ppm, but it's very doubtful that the "boost" mode will be enough to oxidize your bather waste and you'll want to check the chlorine level after a few hours, 12 hours, and 24 hours to make sure it doesn't get to 0 (or close to it < 1).
A spa is VERY different than a pool in terms of chlorine demand. In a pool, most chlorine is lost during the day from sunlight and is fairly regular unless your weather is variable. So a single setting (on-time) for a saltwater chlorine generator works well. In a spa, however, it is the bather load that determines the chlorine demand and that is VERY variable in terms of chlorine demand. When there is no bather load and no ozonator, roughly 25% of the FC is lost each day so at 2 ppm FC that would be 0.5 ppm FC per day chlorine usage. 30 minutes of one person soaking in a hot (104ºF) tub of 350 gallons would need around 3.5 ppm FC to oxidize the bather waste. So that's obviously a huge difference. If one doesn't soak every day, then the chlorine demand looks like 0.5, 0.5, 3.5, 0.5, 0.5, ... so very spiky. If one soaks every day, then it's more consistent at 3.5, 3.5, 3.5, ... so the saltwater chlorine generator could be set to handle this though you'd still need to use the "boost" mode so that most of the chlorine generation is right after the soak, otherwise the FC can get used up and get to 0.
So the bottom line is that a saltwater chlorine generator in a spa is really only useful to generate a background of chlorine in between soaks if you do not use the spa every day. In most cases, you still need to manually add chlorine after your soak unless you soak every day and the "boost" mode happens to be strong enough to prevent the chlorine from staying near 0 ppm for longer than about an hour after your soak.
A spa is VERY different than a pool in terms of chlorine demand. In a pool, most chlorine is lost during the day from sunlight and is fairly regular unless your weather is variable. So a single setting (on-time) for a saltwater chlorine generator works well. In a spa, however, it is the bather load that determines the chlorine demand and that is VERY variable in terms of chlorine demand. When there is no bather load and no ozonator, roughly 25% of the FC is lost each day so at 2 ppm FC that would be 0.5 ppm FC per day chlorine usage. 30 minutes of one person soaking in a hot (104ºF) tub of 350 gallons would need around 3.5 ppm FC to oxidize the bather waste. So that's obviously a huge difference. If one doesn't soak every day, then the chlorine demand looks like 0.5, 0.5, 3.5, 0.5, 0.5, ... so very spiky. If one soaks every day, then it's more consistent at 3.5, 3.5, 3.5, ... so the saltwater chlorine generator could be set to handle this though you'd still need to use the "boost" mode so that most of the chlorine generation is right after the soak, otherwise the FC can get used up and get to 0.
So the bottom line is that a saltwater chlorine generator in a spa is really only useful to generate a background of chlorine in between soaks if you do not use the spa every day. In most cases, you still need to manually add chlorine after your soak unless you soak every day and the "boost" mode happens to be strong enough to prevent the chlorine from staying near 0 ppm for longer than about an hour after your soak.
Thank you for your detailed reply. Last question...I do have a Taylor test kit. My question is,do you recommend any test strips I could use when I do not have the extra time to use the Taylor kit?
Test strips aren't consistently good enough to recommend them, but at least the chlorine tests aren't as bad as some others. You'll just have to see for yourself if any are good enough by comparing against the gold standard of the FAS-DPD chlorine test. I don't have enough experience with them to recommend any one in particular. However, the more frequent testing I was describing is just initially until you get things set up and understand your spa and the chlorine generator. Once things are dialed in you may not need to test as frequently.
The advantage of the saltwater chlorine generator for a spa is if you aren't using the spa every day or two. In that case, it gives you a way of automatically adding chlorine in between soaks. It does not eliminate the need for adding chlorine after your soak (except for some limited situations I described earlier) and it does not eliminate the need for testing though if you have a fairly regular pattern you can usually back off on testing quite as frequently (it's really up to you -- you have to assess the risk/convenience tradeoff yourself).
The advantage of the saltwater chlorine generator for a spa is if you aren't using the spa every day or two. In that case, it gives you a way of automatically adding chlorine in between soaks. It does not eliminate the need for adding chlorine after your soak (except for some limited situations I described earlier) and it does not eliminate the need for testing though if you have a fairly regular pattern you can usually back off on testing quite as frequently (it's really up to you -- you have to assess the risk/convenience tradeoff yourself).
I don't see how it's any cheaper. You still need to use either chlorine or even more expensive MPS with Nature2. You can't use Nature2 alone as it is not a disinfectant. It's only the silver ions in Nature2 in combination with MPS that are a disinfectant (at hot spa temps). With chlorine, there isn't a need for the Nature2. People who have thought that Nature2 would keep their water clear if the chlorine went to zero have been disappointed.
One more question....I know with my pool if you kill all the organics and a cc of .5 or zero there is no chlorine smell. Is it the same for a spa? I have not used my hot tub in 2 years. One reason I was out of work for a while so keep electric bill down and I could not take the smell of bromine and the way it dried out my skin. I want to start using it again but not sure what to use as a sanitizer.
It's not quite the same because the spa water temperature is quite a bit hotter so the volatility is greater and there are often aeration jets used that increase outgassing rates. So usually for a spa we recommend starting one's soak no higher than 2 ppm FC (but not less than 1 ppm FC) which will tend to keep any smell of chlorine or chloramine to a minimum. If you instead soak with enough chlorine to last through your entire soak (for a 350 gallon tub say 4 ppm for a half-hour or 7 ppm for an hour), you'll likely smell some chlorine as well as chloramine (mostly monochloramine). You would do the latter if you were soaking with strangers where person-to-person transmission of disease was to be avoided.
Once you get out of the tub and add the appropriate amount of chlorine to it to handle the bather waste, any pathogens getting into the tub will get killed. Even the monochloramine will tend to keep them in check during your soak, but the blast of chlorine after your soak does them in including preventing biofilm formation.
As for whether to go with chlorine, it really depends on how frequently you soak and whether you have an ozonator. If you don't soak every day or two then whether you are able/willing to add chlorine every day or two (if needed). Yes, some people don't like the smell of bromine so perhaps you can start out with chlorine using the Dichlor-then-bleach method and see if it works for you. Just remember that you need to get your TA quite low (to 50 ppm, if needed) and that 50 ppm Borates are also recommended as well as 120-150 ppm CH to help prevent foaming. If your spa is new or wasn't properly disinfected, then use Spa System Flush as well as superchlorination to clean it thoroughly.
Once you get out of the tub and add the appropriate amount of chlorine to it to handle the bather waste, any pathogens getting into the tub will get killed. Even the monochloramine will tend to keep them in check during your soak, but the blast of chlorine after your soak does them in including preventing biofilm formation.
As for whether to go with chlorine, it really depends on how frequently you soak and whether you have an ozonator. If you don't soak every day or two then whether you are able/willing to add chlorine every day or two (if needed). Yes, some people don't like the smell of bromine so perhaps you can start out with chlorine using the Dichlor-then-bleach method and see if it works for you. Just remember that you need to get your TA quite low (to 50 ppm, if needed) and that 50 ppm Borates are also recommended as well as 120-150 ppm CH to help prevent foaming. If your spa is new or wasn't properly disinfected, then use Spa System Flush as well as superchlorination to clean it thoroughly.
Thanks, I ordered the swg but I think i will return. I'm starting to think its not worth the high price since i am adding chlorine anyway. Thank you for the detailed answer
I wanted you to make sure you read this thread and this thread. It does appear that users are able to dial in a setting and use boost mode and be able to get reasonable chlorine levels that aren't too high or too low. I do think that it might be difficult for those who use the spa less frequently but with high bather load, but for those using a spa somewhat regularly (every day or two) it does seem to work quite well.
I just didn't want my earlier comments to unnecessarily dissuade you.
I just didn't want my earlier comments to unnecessarily dissuade you.
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