Nature2 - How Much Chlorine?

[Matt38]

I bought a tub a few years back and have been using chemgeek's dichlor/bleach method pretty successfully. Lately I've had less time for the tub and found myself getting too lax on maintanining the FC using the tub 2x a week and decided to give Nature2 a spin.

I'm about one week into a new fill with Nature2 and am happy thus far. I've found the Nature2 test strips to be pretty good for TA and PH suprisingly.

I'm a bit confused on the "low chlorine cocktail". The instructions indicate an initial shock with dichlor to sanitize and activate the cartridge. Then you basically keep your MPS in range by testing before/after each use (what a pain ... I'm sure you just figure out how much post-use MPS keeps you at an acceptable level for the next use and then shock after use). I've spent a couple hours tonight trying to find an exisiting post on the topic, but I have had no luck.

Does the addtion of the MPS reactivate combined chlorine to maintain a "low chlorine cocktail" (I think not) or is shocking with dichlor every week or two actually required rather than "as needed" as the insructions indicate? Plus they dont' say anything about CYA, so after a month I've got 30ppm CYA and rising on a four month cycle. I would assume I should switch to bleach after 20ppm CYA. This is driving me crazy. I'm the only one that uses the tub and am generally a low bather load so I'm expecting to not shock as offten as they indicate, but time will tell.

Basically if shocking with MPS does the job do I ever have to add Chlorine after the initial start up dichlor? I'm sure the answer will be "you will have to use Chlorine just wait", but from a SANITIZING stand point, the way I read things Ag ions & MPS @ >100F is all the sanitizer I need to keep from getting sick? I come accross people talking about minimum FC with Nature2, but the instructions don't say jack about FC levels whatsoever.

I would appreciate any info.

Thanks,

Matt

[chem geek]

I'm a bit confused on the "low chlorine cocktail". The instructions indicate an initial shock with dichlor to sanitize and activate the cartridge. Then you basically keep your MPS in range by testing before/after each use (what a pain ... I'm sure you just figure out how much post-use MPS keeps you at an acceptable level for the next use and then shock after use). I've spent a couple hours tonight trying to find an exisiting post on the topic, but I have had no luck.

Does the addtion of the MPS reactivate combined chlorine to maintain a "low chlorine cocktail" (I think not) or is shocking with dichlor every week or two actually required rather than "as needed" as the insructions indicate? Plus they dont' say anything about CYA, so after a month I've got 30ppm CYA and rising on a four month cycle. I would assume I should switch to bleach after 20ppm CYA. This is driving me crazy. I'm the only one that uses the tub and am generally a low bather load so I'm expecting to not shock as offten as they indicate, but time will tell.

Basically if shocking with MPS does the job do I ever have to add Chlorine after the initial start up dichlor? I'm sure the answer will be "you will have to use Chlorine just wait", but from a SANITIZING stand point, the way I read things Ag ions & MPS @ >100F is all the sanitizer I need to keep from getting sick? I come accross people talking about minimum FC with Nature2, but the instructions don't say jack about FC levels whatsoever.

Matt,

The silver ions from the Nature² cartridge plus the MPS you add and the water being hot all combine to make the water sanitary. This combination has passed the very stringent EPA DIS/TSS-12. You do not need any chlorine to keep the spa sanitary so long as you maintain the MPS level. However, MPS does not oxidize the same things that chlorine does so you may find that you need to shock with chlorine once a week or two, but you can just see how things go and shock "as needed", just as the instructions say.

If you do not have an ozonator, then the amount of MPS you would need should be roughly 7 teaspoons for every person-hour of soaking, plus whatever is needed for the residual MPS to last until your next soak. I don't know if MPS lasts longer than chlorine, but I hope it does since the main reason you are switching is that you don't want to add sanitizer as frequently between soaks (do you have an ozonator? if so, then that would consume more chlorine between soaks, but shouldn't affect MPS).

You don't "shock" with MPS. The MPS is used as an oxidizer for your bather waste and the residual MPS is used as a sanitizer when combined with silver ions and hot water temperatures. You do not need any minimum FC level for this -- just an MPS level.

As for the Dichlor and CYA, you won't be using as much Dichlor so probably don't need to worry about the CYA buildup. If for some reason you do use a lot of Dichlor, then yes you could switch to bleach at some point, but I suspect you won't be needing to shock very often with chlorine so could just use Dichlor if you wanted. I wouldn't use only bleach since the chlorine would then be too strong and any soak soon afterward might be too harsh (and possibly smell of chlorine).

People who don't soak frequently usually find that bromine works better for them because the bromine tabs in a floating feeder usually last at least a week, but let us know how the N2 with MPS works for you and if the MPS lasts long enough between soaks.

Richard

[Matt38]

I'm a bit confused on the "low chlorine cocktail". The instructions indicate an initial shock with dichlor to sanitize and activate the cartridge. Then you basically keep your MPS in range by testing before/after each use (what a pain ... I'm sure you just figure out how much post-use MPS keeps you at an acceptable level for the next use and then shock after use). I've spent a couple hours tonight trying to find an exisiting post on the topic, but I have had no luck.

Does the addtion of the MPS reactivate combined chlorine to maintain a "low chlorine cocktail" (I think not) or is shocking with dichlor every week or two actually required rather than "as needed" as the insructions indicate? Plus they dont' say anything about CYA, so after a month I've got 30ppm CYA and rising on a four month cycle. I would assume I should switch to bleach after 20ppm CYA. This is driving me crazy. I'm the only one that uses the tub and am generally a low bather load so I'm expecting to not shock as offten as they indicate, but time will tell.

Basically if shocking with MPS does the job do I ever have to add Chlorine after the initial start up dichlor? I'm sure the answer will be "you will have to use Chlorine just wait", but from a SANITIZING stand point, the way I read things Ag ions & MPS @ >100F is all the sanitizer I need to keep from getting sick? I come accross people talking about minimum FC with Nature2, but the instructions don't say jack about FC levels whatsoever.

Matt,

The silver ions from the Nature² cartridge plus the MPS you add and the water being hot all combine to make the water sanitary. This combination has passed the very stringent EPA DIS/TSS-12. You do not need any chlorine to keep the spa sanitary so long as you maintain the MPS level. However, MPS does not oxidize the same things that chlorine does so you may find that you need to shock with chlorine once a week or two, but you can just see how things go and shock "as needed", just as the instructions say.

If you do not have an ozonator, then the amount of MPS you would need should be roughly 7 teaspoons for every person-hour of soaking, plus whatever is needed for the residual MPS to last until your next soak. I don't know if MPS lasts longer than chlorine, but I hope it does since the main reason you are switching is that you don't want to add sanitizer as frequently between soaks (do you have an ozonator? if so, then that would consume more chlorine between soaks, but shouldn't affect MPS).

You don't "shock" with MPS. The MPS is used as an oxidizer for your bather waste and the residual MPS is used as a sanitizer when combined with silver ions and hot water temperatures. You do not need any minimum FC level for this -- just an MPS level.

As for the Dichlor and CYA, you won't be using as much Dichlor so probably don't need to worry about the CYA buildup. If for some reason you do use a lot of Dichlor, then yes you could switch to bleach at some point, but I suspect you won't be needing to shock very often with chlorine so could just use Dichlor if you wanted. I wouldn't use only bleach since the chlorine would then be too strong and any soak soon afterward might be too harsh (and possibly smell of chlorine).

People who don't soak frequently usually find that bromine works better for them because the bromine tabs in a floating feeder usually last at least a week, but let us know how the N2 with MPS works for you and if the MPS lasts long enough between soaks.

Richard

Thanks Richard. What you said is what I sort of suspected, but seeing people talk about ppm FC, "low chlorine cocktail", and "shock as needed" with dichlor had me wondering and I don't want to mess around with dirty water. I didn't meantion this before but I want to reduce my halogens exposure and the time I tried Br I was not a fan. I realize Br/Ozone makes for a great low maintenance tub, but I don't want to soak in the stuff! So far I've been adding MPS on the skinny side and it's not quite enough. Once I get a feel for how it works as far as maintenace I'll report back.

I was aware that a little CYA is required before using bleach, but if I shock with dichlor to the tune of 10ppm once a week, that's almost 40 ppm CYA per month. Since Nature 2 recommends a 4 month cycle that's approaching 160ppm CYA at the end of the cycle (assuming I shock 10ppm dichlor/week). I'll count up to about 25 ppm dichrol and then switch to bleach.

Will you please differentiate shocking a tub vs. adding oxidizer? While I was using using the dichlor/bleach method I always was under the impression I was hyperchloronating to shock AKA oxidize out the contaminates including combined Chlorine. It gets kind of weird.... the MPS is part of the sanatizer for a N2 tub, but is not used for shocking while A Br tub can be shocked with MPS right? Could one not "shock" with a larger dose of MPS? Maybe your answer is going to be MPS only shocks Br because it restores the free Bromine. Chlorine truely is beautiful

[waterbear]

I didn't meantion this before but I want to reduce my halogens exposure and the time I tried Br I was not a fan. I realize Br/Ozone makes for a great low maintenance tub, but I don't want to soak in the stuff!

I sense a red flag here! What is your reason? There is a lot of misunderstanding and bad press about halogens BUT they deal with drinking water and disinfection byproducts in indoor pools. Also, MPS is an irritant creates a high sulfate level in the water.

Will you please differentiate shocking a tub vs. adding oxidizer?

Shocking is superoxidining. Shock is used very loosely by most people and can refer to a procedure or to a product BUT there really isn't a special "shock" product. The "shocks" used in pools and spas are all oxidizers (chlorine, bromine, MPS, and for biguanide spas hydrogen peroxide). The term is also used differently, depending on the sanitizer (since their chemistry is not the same.)

For chlorine it means adding enough excess oxidizer to break down choramines and other organic waste. The oxidizers used are either chlorine (superchlorination) or MPS. Since MPS does not raise chlorine levels there is less waiting before you can reenter the water.

For Bromine it means adding enough excess oxidizer to create a high bromine level (superbrominating) to break down bromamines and other organics. While bromamines are effective sanitizers (unlike cloramines) they have a distinct odor that many people find objectionable and regular "shocking" can keep them in check. Note that it does not matter whether the oxidizer used is chlorine or MPS since both will cause a rise in bromine (assuming a bromide reserve in the water) and the waiting time before entering the water will be the same so the main advantage of shocking a chlorine spa with MPS does not exist with bromine.

Hydrogen peroxide is really only used with biguanide (a non halogen sanitizer) since biguanide is not an oxidizer. It is EPA approved but it is very expensive compared to halogen or silver/mps systems and has other drawbacks. However, for those with a true halogen allergy (rare) it is an option since all other EPA approved sanitizers do include halogens in the mix (including N2). Peroxide by itself needs to be used at a high level to be a primary sanitizer and can be irritating (It is NOT an EPA approved sanitizer. In biguanide systems the biguanide is the santizer and peroxide is the oxidizer).

Silver/MPS/Heat with chlorine at needed IS an EPA approved santizer. MPS cannot be used to 'shock' such a system and the 'recipe' HAS changed over the years since it was first introduced. It was originally introduced as a no chlorine system but that did not pass the tests. Then the a "low chlorine recipe" (a true low chlorine recipe with residual FC of .5 ppm) with weekly MPS shocking was introduces but that also did not pass the test since the amount of residual chlorine in the tub was way too low and the amount of MPS being used was also way too low. Then the "New" low chlorine recipe was introduced around 2004 if memory serves me correctly which used higher amount of chlorine and MPS AND required weekly or as needed shocking with chlorine and a much higher residual MPS level in the water. The kicker is the "as needed" which, in a heavily used tub, could be several times a week (which means that there would always be a chlorine residual in the water, which means you have a chlorine tub).

When the "new" recipe was introduced the instruction booklet said that dichlor could be substituted for the MPS if desired. I worked out the FC levels if only dichlor was used and posted the results in another pool forum (and later on here) AND GUESS WHAT? FC levels worked out to be the recommended levels for both residual and for shocking for a chlorine spa without a Nature 2 cart!!!!!!! In other words, if you are not using MPS then the N2 cart does nothing! If you are using MPS then you still need chlorine because the silver/MPS on it's own can't keep up AND STILL NEEDS HELP FROM AN ADDITIONAL SANTIZER! (The 'shocking' in this case is actually superchlorinating and the reason it requires chlorine is because it needs a sanitizer and not just an oxidizer added!)

Finally, Silver/MPS is much more expensive than either chlorine or bromine.

FWIW, there is another silver/MPS system called SilSpa by N.Jonas. It does not use a cartridge to add the silver to the water but rather introduces the silver as a liquid.

While I was using using the dichlor/bleach method I always was under the impression I was hyperchloronating to shock AKA oxidize out the contaminates including combined Chlorine.

Yes, but MPS can also be used to oxidize a chlorine system. It works differently however. When you "shock" with chlorine you are breaking chlorine/ammonia bonds and thereby destroying chloramines (chlorine/ammonia compounds). When you shock with MPS you are oxidizing ammonia compounds BEFORE they combine with the chlorine and prevent the formation of chloramines. Note that MPS is not as effective as chlorine at destroying existing chloramines. In some cases, both approaches are needed, such as indoor pools or chlorine spas with persistent combined chlorine problems.

It gets kind of weird.... the MPS is part of the sanatizer for a N2 tub, but is not used for shocking while A Br tub can be shocked with MPS right?

The chemistry is not the same. Apples and Oranges.

Could one not "shock" with a larger dose of MPS?

The problem is the work "shock". It means many different things, depending on the context and the primary sanitizer. MPS CAN be used to shock with chlorine (but does not shock in the same way as adding as superchlorination), it can be used to shock with bromine (by converting bromide into hypobromous acid and thereby superbrominating, chlorine does exactly the same thing in a bromine system.)

It is NOT used to shock a silver/mps system (chlorine is used here since shocking means adding a high dose of santizer to kill anything that has started growing so the silver/MPS can keep up since the residual level of MPS in the water is effectively keep the organics oxidized) nor a biguanide system such as BaquaSpa or SoftSoak (MPS and halogens are not compatible with biguanide and will create problems if added, not to mention a lot of "goo" and yucky colored water).

Maybe your answer is going to be MPS only shocks Br because it restores the free Bromine.

Yep.

Chlorine truely is beautiful

Hope this clears some things up for you.

[chem geek]

Yeah, "shock" is an imprecise term. What waterbear refers to above is where additional oxidizer added to meet higher bather-load would be shocking the spa. For me, I call that just using enough oxidizer to handle bather waste and I reserve the term "shocking" to mean what is done when there is a problem noted, either cloudy water or high Combined Chlorine (CC) where one raises the Free Chlorine (FC) or oxidizer level much higher than the background level in order to get rid of the problem or when one adds additional oxidizer on a regular (usually weekly) basis to avoid such a problem. This is why I say that one rarely, if ever, needs to shock a properly managed chlorinated pool or spa. Sorry for the confusion. We'll have to sort out our terminology for consistency, even between ourselves!

Two other points. The Nature2/MPS EPA submissions (I can't find them right now, but I've seen them before) showing fast bacterial kill were without any residual chlorine level, though were at hot spa temperatures. However, MPS by itself may not be enough to keep the water clear over time (with use from bather load) which is why the chlorine "as needed" is suggested. The second interesting fact is that MPS doesn't actually react with ammonia very quickly (see this paper) which surprised me. So using MPS in a chlorinated pool or spa doesn't actually react with ammonia before chlorine does to form monochloramine. Dupont has verified this with me though they couldn't rule out the possibility of catalysis in real pool water (say from metal ions). It is unclear what happens in a Nature2/MPS situation with regard to ammonia.

Anyway, I agree with waterbear that Nature2/MPS is a lot more expensive and generally still needs some chlorine periodically to keep the water in good shape. Avoiding the disinfection by-products from halogen-based methods (i.e. chlorine or bromine) is a personal choice, but I agree with waterbear that it's not a significant risk based on what we know to date. It's not that there aren't risks, but as I've written elsewhere, they are in the 1 in 100,000 to 1 in 1,000,000 range of increased risk of cancer based on linear dose models for the trihalomethanes (mostly the brominated ones) and on mutagenicity studies of the water overall.

[op1]

Wow all I wanted to do was have a spa to soak my bones in. Now I'm learning chemistry.

OP1

[Matt38]

Yeah, "shock" is an imprecise term. What waterbear refers to above is where additional oxidizer added to meet higher bather-load would be shocking the spa. For me, I call that just using enough oxidizer to handle bather waste and I reserve the term "shocking" to mean what is done when there is a problem noted, either cloudy water or high Combined Chlorine (CC) where one raises the Free Chlorine (FC) or oxidizer level much higher than the background level in order to get rid of the problem or when one adds additional oxidizer on a regular (usually weekly) basis to avoid such a problem. This is why I say that one rarely, if ever, needs to shock a properly managed chlorinated pool or spa. Sorry for the confusion. We'll have to sort out our terminology for consistency, even between ourselves!

Two other points. The Nature2/MPS EPA submissions (I can't find them right now, but I've seen them before) showing fast bacterial kill were without any residual chlorine level, though were at hot spa temperatures. However, MPS by itself may not be enough to keep the water clear over time (with use from bather load) which is why the chlorine "as needed" is suggested. The second interesting fact is that MPS doesn't actually react with ammonia very quickly (see this paper) which surprised me. So using MPS in a chlorinated pool or spa doesn't actually react with ammonia before chlorine does to form monochloramine. Dupont has verified this with me though they couldn't rule out the possibility of catalysis in real pool water (say from metal ions). It is unclear what happens in a Nature2/MPS situation with regard to ammonia.

Anyway, I agree with waterbear that Nature2/MPS is a lot more expensive and generally still needs some chlorine periodically to keep the water in good shape. Avoiding the disinfection by-products from halogen-based methods (i.e. chlorine or bromine) is a personal choice, but I agree with waterbear that it's not a significant risk based on what we know to date. It's not that there aren't risks, but as I've written elsewhere, they are in the 1 in 100,000 to 1 in 1,000,000 range of increased risk of cancer based on linear dose models for the trihalomethanes (mostly the brominated ones) and on mutagenicity studies of the water overall.

Thanks Waterbear and Chemgeek. As you can see you both have a different opinion about the the requirement or lack there of for the need to have a constant free chlorine level. I have read the instructions ten times and know for a fact that chlorine monitoring is not mentioned, but then again I'm open to different interpretations of how the test was designed or the data analyzed so I'm still wondering. If they did indeed pass the test with 0 FC then there's the answer. I'll try to see if I can find this info to help the cause. LIke you both say though, I'll likely shock with Chlorine enough for it to be hard not to have some FC anyway. Waterbear if you can dig up any info on the requirement of FC with N2 I'd love to review it.

Waterbear... my reasons for avoiding halogens can be found in the book "Iodine, Why you need it" Chapter 5 written by David Brownstein, M.D. (ISBN 978-0-9660882-3-6). I'm not prepared to defend his accusations, but his reasoning was enough to get my attention. I do not have 100% faith in how we access toxicity as it lacks long term exposure analysis in many cases (there are likely TONS of studies on Chlorine/Bromine though) as well as how chemicals in general interact and possibly disrupt a person's very delicate and intricate endocrine system. If an experiment is designed poorly or deceitfully due to who is funding the research, variables and the handling of uncertainties can be used to make a undesirable result fall into the noise. This could be said for the lack of negative effects of halogens or the efficacy of Nature2 for that matter. Anyway I'm not all hardcore about this, rather I'd like to give N2 a spin. If I can manage to only have to screw with hot tub chemicals every few days (when I use the tub) it will be worth the extra expense of N2 cartridges (66 dollars a year) and MPS, which is expensive plus the MPS test supplies. As it stands now I throw away my filter after one use because I don't want to mess with cleaning them and the associated chemicals, so I'm not a money miser when it comes to running the tub. If the MPS is as needy as Chlorine then it starts to become a harder decision for me. I'll see how this fill plays out and go from there.

I'll do some more research on N2 and report back if I find anything worthwhile.

Thanks again for taking the time to write your responses.

[waterbear]

Reread what I said. I think you will find that chem geek and I said basically the same thing. silver/mps/hot water IS an EPA approved santizer even with no FC (it was the old recipe that required the .5 ppm FC level and was changed a few years back). However, the N2 system still does require weekly or as needed 'shocking with chlorine. In actual practice the 'as needed' for many users of the system becomes more than weekly. Also, as I stated, if you read the instructions that came with your N2 it says that you can substitute dichlor for the MPS but if you do then you are running normal and not reduced FC levels in your spa (which the instructions do not mention).

As for the good doctor you mention, I have not read his book but I have now read several things he has on the interinet including this and from what I can it is referring to ingested bromine and chlorine which is pretty much standard as I stated before and has little to do with their use as sanitizers. Also, many of his statements refer to elemental bromine (which is not used in hot tubs) and he makes reference to ingested bromates (which he incorrectly refers to as bromine when he references the 'oxidized form of bromide'. The good doctor needs to review his basic college chemistry since this particular presentation contains almost as many errors as the average explanation of spa water chemistry that a majority of dealers who have been trained by the chemical distributors regurgitate to consumers.

[chem geek]

In particular, with regard to chlorine in the presentation waterbear linked to, the statement that for chlorine a "by-product is dioxin (one of the most carcinogenic agents known, with toxicity second only to radioactive waste!)" is extremely irresponsible, at least with regards to use of chlorine as a disinfectant in "hot tubs, swimming pools, chlorinated water". Dioxins are formed at high temperatures from organic chemicals in the presence of chlorine so are produced in waste incinerators when exhaust gasses cool. Modern incinerators avoid the problem by using higher incineration temperatures (1000ºC) and rapid cooling of exhaust gasses (below 400ºC) and have significantly reduced dioxins as a result. Dioxins are also formed from the chlorine bleaching of fibers and textiles, but at very high chlorine concentrations usually using chlorine gas. Modern bleaching techniques now use alternatives such as chlorine dioxide, oxygen, ozone and hydrogen peroxide. In all of the studies testing for chlorinated organic compounds in pool or spa water, dioxin has never been found. This study had a comprehensive identification of disinfection by-products in high bather load chlorinated and brominated indoor pools where, out of 108 compounds found, dioxin is not among them (which is, of course, no surprise). In spite of being high bather load pools, the water was found to be as mutagenic at levels similar to treated drinking water.

[Matt38]

In particular, with regard to chlorine in the presentation waterbear linked to, the statement that for chlorine a "by-product is dioxin (one of the most carcinogenic agents known, with toxicity second only to radioactive waste!)" is extremely irresponsible, at least with regards to use of chlorine as a disinfectant in "hot tubs, swimming pools, chlorinated water". Dioxins are formed at high temperatures from organic chemicals in the presence of chlorine so are produced in waste incinerators when exhaust gasses cool. Modern incinerators avoid the problem by using higher incineration temperatures (1000ºC) and rapid cooling of exhaust gasses (below 400ºC) and have significantly reduced dioxins as a result. Dioxins are also formed from the chlorine bleaching of fibers and textiles, but at very high chlorine concentrations usually using chlorine gas. Modern bleaching techniques now use alternatives such as chlorine dioxide, oxygen, ozone and hydrogen peroxide. In all of the studies testing for chlorinated organic compounds in pool or spa water, dioxin has never been found. This study had a comprehensive identification of disinfection by-products in high bather load chlorinated and brominated indoor pools where, out of 108 compounds found, dioxin is not among them (which is, of course, no surprise). In spite of being high bather load pools, the water was found to be as mutagenic at levels similar to treated drinking water.

Waterbear/Chemgeek,

Sounds like he is making incorrect statements. He is not referring to halogens used specifically for water maintenance, rather products and food sources. My primary reason for trying N2 is less maintenance so the halogen thing is not an issue. Waterbear... after reading your post again I understand. I'll see what my low-bather-load tub requires as far as MPS maintenance and hyperchlorination and go from there.

It sounds like the answer to my question is basically "No, Chlorine is not required to have an adequate sanitizer, but what you will find is you will have to use Chlorine to keep the tub's water clear and fresh resulting in residual chlorine, particularly if you have higher bather loads."

If I have to add MPS as much as I was adding chlorine and am having to shock with Chlorine I'll likely switch back to Chlorine only. I can say that I really like the feel and smell of the water, but I'm only a week in and everything is nice with fresh water.

Thanks for sounding in with your experience.

Matt

[waterbear]

IMHO, N2 is not any easier than chlorine but quite a bit more expensive. Instead of making sure there is a FC residual in the water before and after each use you must make sure there is an MPS residual and you still need to shock with chlorine. You have the additional expense of the the cartridges, the special test strips to test for MPS, and the larger quantities of MPS required (and MPS tends to be much more expensive than chlorine.

If you are looking for less work and maintenance then I am afraid that you are stuck with three step bromine.

[Matt38]

IMHO, N2 is not any easier than chlorine but quite a bit more expensive. Instead of making sure there is a FC residual in the water before and after each use you must make sure there is an MPS residual and you still need to shock with chlorine. You have the additional expense of the the cartridges, the special test strips to test for MPS, and the larger quantities of MPS required (and MPS tends to be much more expensive than chlorine.

If you are looking for less work and maintenance then I am afraid that you are stuck with three step bromine.

Thanks Again.

[Matt38]

Well it's been just over a month and I though I would report back.

I have not had to shock with Chlorine and the water is crystal clear still. I use the tube four to five times a week for ~ 20 minutes. I use mineral salt deodorant and no other products that leave residuals so that might be why I'm not having to shock (so far). Occasionally there is some scum on the side of the tub, but it quickly dissolves and ends up in the filter after it's run for a minute (slightly more than I experienced with chlorine). I has been very windy here so that might be the cause of the scum. Overall I like it much more than Chlorine. While it's not as maintenance free as I was hoping, I find that it's easier than chlorine. After I get out I put one tablespoon of MPS in and know that it will last for about three days. At the three day point the test strip indicates the MPS is low, but not gone (if you are familiar with the strips). I'm assuming this is still pretty safe since no one else is using it and it's not MPS free (maybe you guys can school me on this assumption). With Chlorine I could not ignore the tub for a couple days and come back problem free so I started putting more in case I didn't come back. Anyway I'm sure I was not doing it perfectly. I've also found that the ph and alkalinity has maintained all month at about 60 and 7.4 respectively. With Chlorine it was always rising. The test strips are more expensive, but now that I know how the tub behaves I don't use them as much, but enough to make sure the MPS demand is not changing. Yes they are expensive, but I've found them to be pretty good actually (had some baquspa strips years ago that were worthless) and I can test three things in ten seconds. The water is essentially odorless to me and I don't feel the need to take a shower after use. I no longer smell the chlorine reactivating or whatever it is I smell after jumping in the shower post tube use (probably combined Chlorine reacting with FC in city water). I am using MPS at the rate of one pound per month, or about $3.50 (buying the bigger container) per month. I'm estimating that I will spend 150 dollars a year on N2 cartridges, MPS and test strips. I'm not find this too offensive as far as cost. Throw in the dichlor, calcium, acid and a new filter every four months and I'm looking at 250 dollars a year total. I would say my expenses have about doubled. Maybe as the cycle gets near the end it will become less attractive.

My only thoughts at this point are:

Is the tub safe to go in with the MPS slightly low (after three days with a single bather). In other words are the disinfecting properties still effective to some degree or is it like having a 0-.5ppm chlorine tub after a couple days? My hunch is it's not as vulnerable as Chlorine, but that's just an ignorant assumption. Obviously the instructions say add mps to the adequate level before getting in the tub. Is there any data available as far as how effective the cocktail is with lower the specified mps?

Lastly what are the particulars of MPS? Can I throw some in and jump right in? I know with Chlorine 8 or 10ppm is too much to get in with, but I don't see any info or caution as far as throwing in a heap of MPS and jumping in the tub. I'm thinking I'll add a teaspoon of MPS just before I get in the tub if it's been a few days since I last oxidized with MPS.

Thanks!

Matt

[chem geek]

You are fortunate to not need to use chlorine every week or two to keep the water clear. That's probably because you've been relatively clean when getting into the tub. The Nature² instructions say to maintain the MPS level so that you add MPS before your soak if needed based on MPS levels and then again after your soak. That is so the spa remains sanitary during your soak preventing person-to-person transmission of pathogens. That is needed to pass EPA DIS/TSS-12. Most people who use chlorine start with 1-2 ppm FC and that's usually not enough to last through the soak so if you wanted to start with a lower but non-zero level of MPS, then that would be similar. Though technically less safe, it's not usually an issue in residential spas and there isn't enough time for runaway bacterial growth -- adding MPS after the soak will (with silver ions from Nature²) kill off anything introduced during the soak.

MPS will get used up oxidizing bather waste just like chlorine, but once that is done any leftover MPS will tend to last somewhat longer than chlorine in hot water. So as you point out it's easier to maintain the spa if you aren't using it every day.

MPS is net acidic so that's why the pH tends to be stable, though the TA is slowly dropping over time and you'll eventually need to add some baking soda at some point. With chlorine bleach, you have to keep the TA quite low and usually use 50 ppm borates to have the pH be more stable. With Dichlor, it is net acidic similar to MPS.

MPS can be irritating to some people but you can add a small amount before getting into the tub to be on the safe side. The important thing is to never let it get to zero, similar to chlorine. Bacteria can double in population every 15-60 minutes so you want to have disinfectant in the water at all times. The test strips for MPS are reasonable so do test before your soak until you get a handle on your tub's MPS usage pattern.

[hjames710]

Sounds like traditional bromine/chlorine is a lot easier.

[countspacula]

6 to 8 teaspoons granulated chlorine per week, 2 of the shock after each use, simple. forget ph games.

[Matt38]

You are fortunate to not need to use chlorine every week or two to keep the water clear. That's probably because you've been relatively clean when getting into the tub. The Nature² instructions say to maintain the MPS level so that you add MPS before your soak if needed based on MPS levels and then again after your soak. That is so the spa remains sanitary during your soak preventing person-to-person transmission of pathogens. That is needed to pass EPA DIS/TSS-12. Most people who use chlorine start with 1-2 ppm FC and that's usually not enough to last through the soak so if you wanted to start with a lower but non-zero level of MPS, then that would be similar. Though technically less safe, it's not usually an issue in residential spas and there isn't enough time for runaway bacterial growth -- adding MPS after the soak will (with silver ions from Nature²) kill off anything introduced during the soak.

MPS will get used up oxidizing bather waste just like chlorine, but once that is done any leftover MPS will tend to last somewhat longer than chlorine in hot water. So as you point out it's easier to maintain the spa if you aren't using it every day.

MPS is net acidic so that's why the pH tends to be stable, though the TA is slowly dropping over time and you'll eventually need to add some baking soda at some point. With chlorine bleach, you have to keep the TA quite low and usually use 50 ppm borates to have the pH be more stable. With Dichlor, it is net acidic similar to MPS.

MPS can be irritating to some people but you can add a small amount before getting into the tub to be on the safe side. The important thing is to never let it get to zero, similar to chlorine. Bacteria can double in population every 15-60 minutes so you want to have disinfectant in the water at all times. The test strips for MPS are reasonable so do test before your soak until you get a handle on your tub's MPS usage pattern.

Thanks Richard. Sounds like I'm not crazy. I'll keep an eye out for TA dropping. Thought I might of noticed that yesterday. I live in the high desert with 8"/year rain and our soil is average ph 8.2. We have a hard time growing certain trees and plants here because we are highly alkaline (water sits about about 8.2 as well). I have to put about three to four table spoons of acid over several hours (230gallons) at water change just to get the Ph and Alkalinity in range. The fact that MPS is acidic is great. I really like it so far. Have a good holiday. May your tub always be clear w/ 3ppm Cl.

[Wozzy]

The people from nature 2 said you still want to keep your chlorine level at .5 ppm. They say that in most cases the cartridge and mps would be fine. But to meet all EPA guidelines you have to use a little chlorine. Basically doing everything the same as before just adding a lot less chlorine. It's a low chlorine system not chlorine free

[chem geek]

That is not what they say in the Nature² Owner's Manual where the "low-chlorine recipe" has you test the water for the MPS (not chlorine) level and add more MPS to maintain that level. The use of chlorine as a shock treatment is only "as needed" and not on any particular schedule nor do you maintain or measure a chlorine level. The owner's manual has to describe what has been approved by the EPA, at least to call the system a disinfectant or make bacterial-kill claims (which they do). You may use chlorine instead of MPS if you want to, but you do not have to.

Who exactly told you that you have to maintain 0.5 ppm Free Chlorine (FC)? Was this a dealer or someone directly from Zodiac (makers of Nature²)?

[waterbear]

.5 ppm FC is for the pool N2 which is a different system. It is a copper/silver system and .5 ppm is not high enough in acutal practice. In fact, all copper systems should be run at normal chlorine levels based on CYA level.

The spa system is a silver/zinc cartridge and the MPS and hot water are integral parts of the sanitizer. It is a silver/MPS sanitizer system.

The pool N2 is really nothing more than a copper based algaecide because the kill times of copper are too slow to make it an efficient santizier in pool water and the lower temperatures of a pool make MPS ineffective.

[grandee1]

For the past 11 years I have used Nature2 in our Hot Spring Grandee I add two table spoons of MPS 10 min prior to using the tub or just after. I add 5 teaspoons of chlorine once a week and have always had perfect water with no odor. I also have an ozonator that runs 24/7 on the circ pump. I tried the strict MPS route with an ozonator and Nature2 when the tub was new and found we needed the small amount of chlorine each week to keep the water fresh. I could most likely get away with no chlorine now since we use the tub a little less but if a tub is used heavily many will find some chlorine is needed. Everyone has their cocktail but in taking care of pools all my life and this spa for the last eleven, I have found chlorine has its place. You will find if you use Nature2 and an Ozonator any residual chlorine is burned off within 12 hours and there will be no smell left behind. The water in our tub is always crystal clear with no odor.

[chem geek]

.5 ppm FC is for the pool N2 which is a different system. It is a copper/silver system and .5 ppm is not high enough in acutal practice. In fact, all copper systems should be run at normal chlorine levels based on CYA level.

Thanks for reminding me about the pool Nature² system. I often forget about that one. The NSF/ANSI Standard 50 minimum is 0.4 ppm chlorine or 0.8 ppm bromine for pools with metal ion generators. I agree that this is, in practice, too low to be able to manage effectively in an outdoor pool. If there is Cyanuric Acid (CYA) in the water, then this chlorine level is too low to oxidize chemicals quickly (or to prevent algae, but that is presumably what the copper is for) so one could get cloudy water at such low levels. In commercial/public pools with supplemental oxidation systems or with no CYA (e.g. the DIN 19643 standard in Europe), that's a different matter, but even there they have a hard time maintaining the low end of their 0.3 to 0.6 ppm range (0.2 to 0.5 ppm with ozone).

grandee1, thanks for the tips on maintaining a spa using Nature² with MPS and the weekly chlorine dosing. Both MPS and chlorine are selective oxidizers, but chlorine tends to do a better job with more of the bather waste that would otherwise cloud the water. That's why using MPS alone is not enough.

[Matt38]

That is not what they say in the Nature² Owner's Manual where the "low-chlorine recipe" has you test the water for the MPS (not chlorine) level and add more MPS to maintain that level. The use of chlorine as a shock treatment is only "as needed" and not on any particular schedule nor do you maintain or measure a chlorine level. The owner's manual has to describe what has been approved by the EPA, at least to call the system a disinfectant or make bacterial-kill claims (which they do). You may use chlorine instead of MPS if you want to, but you do not have to.

Who exactly told you that you have to maintain 0.5 ppm Free Chlorine (FC)? Was this a dealer or someone directly from Zodiac (makers of Nature²)?

So it has been almost three months now. Other than putting 1 tbsp of dichlor (225 gal tub) in on day one, I have only added MPS and a bit of sodium bicarbonate on three occasions to bump up the alkalinity. The water remains crystal clear and nearly odorless (the MPS has it's own faint smell I think). I much prefer N2 over the bleach (which I believe to be a great method too). For the past couple months the tub has been used five nights a week by two people for ~25min. My MPS consumption has gone up to about 1.25# a month due to heavier use. I have had almost no problem with deposits on the side of the tub, but on a handful of occasions some grime has come out of solution on the side with easy clean up. I'll point out that both the people using this tub don't use make up, hair conditions, or slimy deodorant. I use Dr. Bronner's Castile soap to shave, wash body and wash hair and then I use mineral salt deodorant which works better than "normal" deodorant for me. This may be why I'm not needing additional Chlorine. I have a feel for how the tub performs now and don't use too many test strips. One of the concerns with this system is the cost of the test strips, but I can't tell you how happy I am to not have to screw around with the chemical set. The tub is more about fun and relaxation lately and less maintenance. Every four months I'll get a new N2 cartridge, new filter (don't want to mess with the cleaning chemicals and the effort), a pack of test strips and five pounds of MPS. Thanks WB and CG for your help.

[chem geek]

I wasn't completely clear on this, but it sounded like you have an ozonator and if that is the case then that may help explain why you've been able to use MPS alone without extra chlorine, though I agree with you that if you are cleaner getting into the spa then there are less chemicals that are harder to break down by ozone or MPS and that chlorine might handle. It's also great that you don't find the MPS to be irritating -- the silver ions in Nature² get rid of the minor contaminant in MPS products that is most irritating, but a few people still have a problem with MPS itself. So I'm glad this is all working out well for you and thanks for the update.

[Matt38]

I wasn't completely clear on this, but it sounded like you have an ozonator and if that is the case then that may help explain why you've been able to use MPS alone without extra chlorine, though I agree with you that if you are cleaner getting into the spa then there are less chemicals that are harder to break down by ozone or MPS and that chlorine might handle. It's also great that you don't find the MPS to be irritating -- the silver ions in Nature² get rid of the minor contaminant in MPS products that is most irritating, but a few people still have a problem with MPS itself. So I'm glad this is all working out well for you and thanks for the update.

Well.... I made it three months before it turned into lemonade! Got sick for five days and ignored it. Went to check on it after five days and it literally looked like lemonade. Big dose of MPS did nothing for it. Decided to change water, filter and N2. Cl might have restored it, but I didn't think to see what it would do before dumping the water. Filter did not look too bad when I pulled it, but it might have been saturated. This next go around I'm going to hit it with Dichlor once a month and see if I can go four months. If not, three months will be good enough for me. Maybe a filter clean at two months is what I needed, but I hate cleaning filters. Thanks.