Best alternative to chlorine/bromine? Any suggestions

[chem geek]

The silver ions will help to prevent uncontrolled bacterial growth, but as shown in this post, silver ions alone effectively have no effect (kill more slowly than reproduction rates) for Acinetobacter baumannii and Legionella pneumophila bacteria.  For keeping bacteria from growing using metal ions, a combination of copper and silver would be better.

Technically, with Nature² you are supposed to maintain an MPS level at all times.  That's why you test the level before you get in to bring it back up if it's too low and then you add more after your soak to handle your bather waste.  You are supposed to add enough to get you through to your next soak, but they don't go into such detail (as is typical for user manuals that keep things overly simplified).

You can probably have the MPS last for at least a week, especially if you drop the water temperature.  I don't know if it will last 3 weeks, however.  Chlorine for sure won't last that long even at cooler temps (it may drop by 10-15% per day so 10 ppm FC after 3 weeks will be 0.1 ppm FC with a 10% per day loss).

If you aren't able to maintain a disinfectant level for extended holiday, then you should decontaminate the spa upon your return and that includes changing the water (i.e. superchlorinate, use Ahh-Some, change the water).  This is being conservative, but then again Legionella isn't something to mess with and we had a report on another forum of a woman who nearly died from it due to a hotel spa that didn't maintain disinfectant nor decontaminate the in-room spa between guests.  See this video or this story and her latest info.

[tobber]

aha, that's interesting.
It is striking that Zodiac doesn't mention that in the manual. For me as a nitwit that isn't clear at all from the manual. In fact, if you read the manual carefully (like i do), then it is very clear that you don't need to monitor the MPS level between soaks. Only before and after you enter the tub. Does Zodiac expect that every owner uses his/her tub every 1 or 2 days?
Isn't that a very dangerous approach? And surprising for a manufacture from a country where you can sue a restaurant for serving too hot coffee or where they warn you in the microwave-manual that you shouldn't put your dog in it (that's the way we in Europe look to the US with off course some exaggeration).

In practice this means that in my case i have to put in some MPS every day, because the level of MPS gets down in 1 or 2 days also if i don't use the tub (maybe because of clearray?)
I think i better use chlorine-tablets in a floater during holidays which the neighbours can add once or twice a week.
Is it okay to put the temperature to the minumum (80 degrees F.) during holidays? Or shut off the electricity completely?

[Isaac-1]

Another potential alternative for you is an SWG (Salt water chlorine generator), if allowed by your manufactuerers warranty, which will generate chlorine in your tub by passing electricity through salt water.  It sounds like an ideal choice for your situation, however due to the corrosive nature of salt water many tub manufactuers say their use will void the tubs warranty.  Those that allow SWG's may do so only for the models that they produce.

Ike

[rosewoodsteel]

I think he was screwing with chem geek. The instructions for N2/MPS specifically say add chlorine.

Sorry for my weak attempt at humor.   

[tobber]

after reading a lot of posts, there is one thing clear for me: "don't mess around with chem geek"   

[Quickbeam]

We don't have a hot tub yet, but hope to get one in the not to distant future. We have friends who do have a tub, and they use hydrogen peroxide as a sanitizer in their tub. They have been using it for some time now, with no ill effects. We have been in their tub and your skin feels silky smooth after a soak. I have talked to a number of hot tub salespeople and so far have not had anyone who has said using hydrogen peroxide will void the warranty. They have said they don't encourage it, but they also tell me the warranty will still be good.

I was looking for somewhere to get the hydrogen peroxide and found a chemical supplier that is close to me. They have nothing to do with hot tubs, they are just a supplier of all kinds of different chemicals. When I called them and told them what I was planning on doing, they said they have a lot of people they sell hydrogen peroxide to for hot tubs and they would be happy to put me in touch with one of their salespeople to guide me in how much to use, etc. I haven't followed up yet, but I will when we get a hot tub.

Again, I can't profess to know a lot about either hot tubs or sanitizers, but we have a friend who uses it and swears by it and I know others use it and claim to be happy. This is what we will be trying when we get a tub.

[chem geek]

aha, that's interesting.
It is striking that Zodiac doesn't mention that in the manual. For me as a nitwit that isn't clear at all from the manual. In fact, if you read the manual carefully (like i do), then it is very clear that you don't need to monitor the MPS level between soaks. Only before and after you enter the tub. Does Zodiac expect that every owner uses his/her tub every 1 or 2 days?
Isn't that a very dangerous approach? And surprising for a manufacture from a country where you can sue a restaurant for serving too hot coffee or where they warn you in the microwave-manual that you shouldn't put your dog in it (that's the way we in Europe look to the US with off course some exaggeration).

In practice this means that in my case i have to put in some MPS every day, because the level of MPS gets down in 1 or 2 days also if i don't use the tub (maybe because of clearray?)
I think i better use chlorine-tablets in a floater during holidays which the neighbours can add once or twice a week.
Is it okay to put the temperature to the minumum (80 degrees F.) during holidays? Or shut off the electricity completely?

If the MPS is getting that low that quickly, then that means you are not adding enough after your soak.  I don't think that the UV from Clearray will have any effect on the MPS.  I believe if you add more MPS after your soak that you should be able to get it to last a week, but note that every week or two you will likely need to add chlorine (usually Dichlor) since MPS doesn't oxidize all bather waste so the water can get dull/cloudy if you never use chlorine.  Since you are only using the spa weekly, you can add MPS and chlorine after your soak and the chlorine should be gone by your next soak while the MPS should still be there (assuming you add enough of both).

The rough rule-of-thumb with no ozonator is that every person-hour of soaking in a hot (104ºF) spa needs 3-1/2 teaspoons of Dichlor or 5 fluid ounces of 6% bleach (or 3-1/2 fluid ounces of 8.25% bleach) or 7 teaspoons of non-chlorine shock (43% MPS) to oxidize the bather waste.

And yes, having the water be cooler should slow down the rate of oxidizer loss.  It's roughly a doubling of chemical reaction rate for every 13ºF degrees though this depends on the specific reactions so is a rough average for what is typically seen.

[chem geek]

We don't have a hot tub yet, but hope to get one in the not to distant future. We have friends who do have a tub, and they use hydrogen peroxide as a sanitizer in their tub. They have been using it for some time now, with no ill effects. We have been in their tub and your skin feels silky smooth after a soak. I have talked to a number of hot tub salespeople and so far have not had anyone who has said using hydrogen peroxide will void the warranty. They have said they don't encourage it, but they also tell me the warranty will still be good.

I was looking for somewhere to get the hydrogen peroxide and found a chemical supplier that is close to me. They have nothing to do with hot tubs, they are just a supplier of all kinds of different chemicals. When I called them and told them what I was planning on doing, they said they have a lot of people they sell hydrogen peroxide to for hot tubs and they would be happy to put me in touch with one of their salespeople to guide me in how much to use, etc. I haven't followed up yet, but I will when we get a hot tub.

Again, I can't profess to know a lot about either hot tubs or sanitizers, but we have a friend who uses it and swears by it and I know others use it and claim to be happy. This is what we will be trying when we get a tub.

To have hydrogen peroxide be effective as a disinfectant, you need it at around 50 ppm concentration and at that level some people find it to be irritating.  It is not approved as a disinfectant by the EPA for the U.S., but Australia approves it for use in spas.  If you want an inexpensive source of hydrogen peroxide, you can get 27% concentration from Baquacil Oxidizer or Aqua Silk Chlorine Free Oxidizer, but that may be more than you need.  You can also get 3% concentration from your local drug store.  50 ppm in 350 gallons would be 223 ml (just under a cup) of 27% while it would be 9-1/3 cups of 3% (it takes more than 9 times as much of the 3% because the density is somewhat lower compared to 27%).

This paper indicates that hydrogen peroxide required higher concentrations of 1000 ppm to kill Legionella pneumophila quickly (99% in 30 minutes) but that 100 ppm killed the bacteria over 24 hours.

[tobber]

Another potential alternative for you is an SWG (Salt water chlorine generator), if allowed by your manufactuerers warranty, which will generate chlorine in your tub by passing electricity through salt water.  It sounds like an ideal choice for your situation, however due to the corrosive nature of salt water many tub manufactuers say their use will void the tubs warranty.  Those that allow SWG's may do so only for the models that they produce.

I have a sundance cameo. I've heard that Sundance doesn't like these SWG's. Also, i think they are not used a lot here in Europe, so there is only a little knowledge from them. My dealer doesn't support them. 
But, i think that during a longer holiday a chlorine-tablet floater will be a good idea.
Or maybe even better, just empty the tub? Is it okay to leave the tub for a few weeks empty? (since it will be during summer, there is no freezing danger)

[tobber]

Since you are only using the spa weekly, you can add MPS and chlorine after your soak and the chlorine should be gone by your next soak while the MPS should still be there (assuming you add enough of both).

The rough rule-of-thumb with no ozonator is that every person-hour of soaking in a hot (104ºF) spa needs 3-1/2 teaspoons of Dichlor or 5 fluid ounces of 6% bleach (or 3-1/2 fluid ounces of 8.25% bleach) or 7 teaspoons of non-chlorine shock (43% MPS) to oxidize the bather waste.

And yes, having the water be cooler should slow down the rate of oxidizer loss.  It's roughly a doubling of chemical reaction rate for every 13ºF degrees though this depends on the specific reactions so is a rough average for what is typically seen.

i use it almost daily, but i was putting things in perspective. Trying to understand what the consequences are.
The amounts you mention are very different from Zodiac. I have a 375gallon tub and i soak with 2 people for an hour. According to the manual i should put in 1,5 tablespoon (4,5 teaspoon). Your advise is 14 teaspoons?
Do i understand this correct?

[Quickbeam]

We don't have a hot tub yet, but hope to get one in the not to distant future. We have friends who do have a tub, and they use hydrogen peroxide as a sanitizer in their tub. They have been using it for some time now, with no ill effects. We have been in their tub and your skin feels silky smooth after a soak. I have talked to a number of hot tub salespeople and so far have not had anyone who has said using hydrogen peroxide will void the warranty. They have said they don't encourage it, but they also tell me the warranty will still be good.

I was looking for somewhere to get the hydrogen peroxide and found a chemical supplier that is close to me. They have nothing to do with hot tubs, they are just a supplier of all kinds of different chemicals. When I called them and told them what I was planning on doing, they said they have a lot of people they sell hydrogen peroxide to for hot tubs and they would be happy to put me in touch with one of their salespeople to guide me in how much to use, etc. I haven't followed up yet, but I will when we get a hot tub.

Again, I can't profess to know a lot about either hot tubs or sanitizers, but we have a friend who uses it and swears by it and I know others use it and claim to be happy. This is what we will be trying when we get a tub.

To have hydrogen peroxide be effective as a disinfectant, you need it at around 50 ppm concentration and at that level some people find it to be irritating.  It is not approved as a disinfectant by the EPA for the U.S., but Australia approves it for use in spas.  If you want an inexpensive source of hydrogen peroxide, you can get 27% concentration from Baquacil Oxidizer or Aqua Silk Chlorine Free Oxidizer, but that may be more than you need.  You can also get 3% concentration from your local drug store.  50 ppm in 350 gallons would be 223 ml (just under a cup) of 27% while it would be 9-1/3 cups of 3% (it takes more than 9 times as much of the 3% because the density is somewhat lower compared to 27%).

This paper indicates that hydrogen peroxide required higher concentrations of 1000 ppm to kill Legionella pneumophila quickly (99% in 30 minutes) but that 100 ppm killed the bacteria over 24 hours.

Thanks Chem Geek,

We plan on using the 27% hydrogen peroxide. As I mentioned, we have found a supplier, although we have not yet asked for any prices. Thanks again for the information.

[chem geek]

But, i think that during a longer holiday a chlorine-tablet floater will be a good idea.

The only chlorine tablets are Trichlor (well, I'm ignoring Cal-Hypo, but they're a mess and not appropriate) and these usually aren't used in a spa because they dissolve too quickly in hot water and you have to be careful about not overdosing which can drive the pH down, exhaust the TA, and damage metal as a result.  If you use a proper floater with a solid top and narrow tube that closes off a lot, then it is OK to use, though it will still be very acidic coming out of the floater and if there is no circulation and the floater parks itself near something, then the acidity could be harsh on nearby spa surfaces (especially metal).

You can certainly drain the tub when you leave but unless you fully remove the water from all lines you'll likely need to decontaminate upon your return and that's a tub full of water to fill, add Ahh-Some, then after running circulation and jets you then drain and fill again.  Another alternative is to keep it full of water, but lower the temperature a lot and perhaps use AquaFinesse to inhibit biofilm formation.  I'd still decontaminate when you return, but at least that's just one drain/refill instead of two.

Basically, not having a disinfectant in the water at all times makes getting bacterial biofilms risky.  If the water was clean with no organics from usage, then the risk is far lower, but think of a spa's initial greases and subsequently your body waste (sweat, urine, dead skin cells) as delicious food for bacteria.

[chem geek]

i use it almost daily, but i was putting things in perspective. Trying to understand what the consequences are.
The amounts you mention are very different from Zodiac. I have a 375gallon tub and i soak with 2 people for an hour. According to the manual i should put in 1,5 tablespoon (4,5 teaspoon). Your advise is 14 teaspoons?
Do i understand this correct?

The Nature² Spa Mineral Sanitizer Owner's Manual from Zodiac Pool Systems says before each use to test the water's MPS level and if low then add 1 tablespoon of MPS per 250 gallons.  It also says to add that amount after each use.  This amount is roughly equivalent to 4 ppm FC in oxidizing power and would roughly handle 35 person-minutes of bather load in 350 gallons, but they do not recognize that the dosing after a soak is independent of spa size and that it should be proportional to bather load.

So yes, their recommendation is significantly underdosing given your relatively high bather load.  However, the actual amount you should dose is whatever it takes so that you don't get too low or to zero in between your soaks.  So adjust up your dosing so that you measure enough MPS for the start of your next soak.  If your spa temperature during the hour of soaking is less than 104ºF, and I suspect that it is since you normally can't soak that long at that high a temperature, then the rule-of-thumb of 7 teaspoons of MPS per person-hour would be lower at the lower temperature.  Also, this rule-of-thumb assumes no ozonator.  With an ozonator, the ozone should handle a lot of the bather load, usually around half.

[tobber]

The only chlorine tablets are Trichlor (well, I'm ignoring Cal-Hypo, but they're a mess and not appropriate) and these usually aren't used in a spa because they dissolve too quickly in hot water and you have to be careful about not overdosing which can drive the pH down, exhaust the TA, and damage metal as a result.  If you use a proper floater with a solid top and narrow tube that closes off a lot, then it is OK to use, though it will still be very acidic coming out of the floater and if there is no circulation and the floater parks itself near something, then the acidity could be harsh on nearby spa surfaces (especially metal).

You can certainly drain the tub when you leave but unless you fully remove the water from all lines you'll likely need to decontaminate upon your return and that's a tub full of water to fill, add Ahh-Some, then after running circulation and jets you then drain and fill again.  Another alternative is to keep it full of water, but lower the temperature a lot and perhaps use AquaFinesse to inhibit biofilm formation.  I'd still decontaminate when you return, but at least that's just one drain/refill instead of two.

Basically, not having a disinfectant in the water at all times makes getting bacterial biofilms risky.  If the water was clean with no organics from usage, then the risk is far lower, but think of a spa's initial greases and subsequently your body waste (sweat, urine, dead skin cells) as delicious food for bacteria.

That's funny, because here they deliver a hottub with 4 things : trichlor tablets, PH- and PH+ and teststrips, "this is all you need, it's real easy, goodluck and byebye!"

If i use the trichlor-tablets, i can combine this with some circulation on 80 degrees F. (minimum temp in sundance). Also i can put the tablets in the brominator (based in skimmer) instead of a floater.
I think it is also possible to keep the circulation going and shutdown the heater for longer time. Then the water will be around 65 degrees F. (average outside temp)


The aquafinesse-idea also sounds interesting. Any idea about the dose if you leave it for 3 weeks?

The Nature² Spa Mineral Sanitizer Owner's Manual from Zodiac Pool Systems says before each use to test the water's MPS level and if low then add 1 tablespoon of MPS per 250 gallons.  It also says to add that amount after each use.  This amount is roughly equivalent to 4 ppm FC in oxidizing power and would roughly handle 35 person-minutes of bather load in 350 gallons, but they do not recognize that the dosing after a soak is independent of spa size and that it should be proportional to bather load.

So yes, their recommendation is significantly underdosing given your relatively high bather load.  However, the actual amount you should dose is whatever it takes so that you don't get too low or to zero in between your soaks.  So adjust up your dosing so that you measure enough MPS for the start of your next soak.  If your spa temperature during the hour of soaking is less than 104ºF, and I suspect that it is since you normally can't soak that long at that high a temperature, then the rule-of-thumb of 7 teaspoons of MPS per person-hour would be lower at the lower temperature.  Also, this rule-of-thumb assumes no ozonator.  With an ozonator, the ozone should handle a lot of the bather load, usually around half.

This i somewhat tricky, because when you leave the tub, you never know when you go again (at least, this is for me the case).
If i dose with 14 teaspoons, then i expect if you go 24 hours later, the MPS level is too high to go in.
But, ok, i think that this will be clear after using it for a longer time. Hopefully it goes with some sort of automatism.
Do you expect that the clearray (and no ozonator) will lower the dose?

[chem geek]

If you don't have the circulation pump always running, then Trichlor tabs will continue to slowly dissolve and the acidity can either migrate to the pump or when the circulation comes back on then a blast of very low pH water hits the pump.  If this is repeated over time, you can end up damaging your pump seals or metal components in the circulation system.  This is seen in pools when people use Trichlor pucks in the skimmer.

The lower temperature will have them dissolve more slowly, but the acidity of Trichlor isn't something you could leave for weeks at a time.  It all depends on the actual chlorine usage, but for every 10 ppm FC from the Trichlor tabs, then when that chlorine is used/consumed the net result is a drop in TA of 7.1 ppm so if you don't restore the TA then it can get depleted, the pH crash, and you end up with a lot of damaged equipment.  Again, this happens in pools that use Trichlor if they are not managed by checking the pH and TA and adjusting as appropriate.

The Clearray (UV) probably won't have any effect.  If anything, it might get rid of some chlorine, but it's really ozone that's worse for that since ozone reacts with chlorine typically doubling 24-hour chlorine demand.  Ozone is great when there is bather load, but not so great when there is not.  For spas not used regularly, ozone is better for a bromine spa since it can make bromine from the bromide bank while it's not so great with a chlorine spa.  I'm presuming the UV from the clearray is rather weak and more in the region for disinfection and not the region for breakdown of chlorine.

What you are looking for is something to maintain your spa for weeks at a time without you having to do anything to the spa.  The AquaFinesse has chemicals that don't normally get used up very quickly so they should last a while.  They are designed to be dosed weekly, but if you dose higher I'd bet that they would last several weeks.  They are mostly surfactants that inhibit bacteria's ability to form biofilms basically making it harder for the sticky chemicals to stick together and hold bacteria to the spa and to each other.  The other longer-term approach would be to use metal ions (silver and copper) in the spa to slow down bacterial growth.  Nature² supplies silver ions, but I've seen reports of spa water still going south if one doesn't have anything but these ions in the water.  None of these are fast acting disinfectants nor oxidizers, but they might be helpful for the long times between your spa uses, though obviously maintaining a disinfectant level would be better.