Dichlor (The Dirty Little Secret)

[canecreek]

Just a quick comment from a new spa owner: I don't (yet) find the _easy_ method easy: reading the dichlor/bleach method and this discussion has made me want to drain the spa and send it back to the store, or push it off a cliff.  

I'm a bright guy by most counts, but I found this thread via Google because I'm having no luck getting the free chlorine reading up and obviously need to do far more studying than I ever anticipated.  Now I should buy a wet chemical test kit?! Man I just want to soak my aching bones.  

I found this forum before I bought a tub and it was fairly helpful then; I have nothing but respect for everyone here. All I'm saying is: don't underestimate the newbieness of the newbie.  

[TubsAndCues]

Just a quick comment from a new spa owner: I don't (yet) find the _easy_ method easy: reading the dichlor/bleach method and this discussion has made me want to drain the spa and send it back to the store, or push it off a cliff.  

I'm a bright guy by most counts, but I found this thread via Google because I'm having no luck getting the free chlorine reading up and obviously need to do far more studying than I ever anticipated.  Now I should buy a wet chemical test kit?! Man I just want to soak my aching bones.  

I found this forum before I bought a tub and it was fairly helpful then; I have nothing but respect for everyone here. All I'm saying is: don't underestimate the newbieness of the newbie.  

That's why I say stick with the dealer you bought your tub from until you get a handle on it.  If you still can't after a few weeks to a month, then test out a different method.  

Many of us on here have differing opinions as to what is the best one, (as can clearly be witnessed here - with emotion at that!) and someone will help you find what is best for your situation.

It's spa owners like you that professionals like myself need to take the time with and show you the easiest and most efficient way for you and your tub, not just a generalized/blanket method.

The best advice I can give you is twofold.  First, don't stress yourself out over it.  It's a hot tub and is meant for you to relax.  Second, don't give up too early before trying a new method.  There is a learning curve, and some people get a grasp of it sooner than others.  Jumping the gun and switching too soon can cause more headaches than solutions.

Best of luck to you, and don't forget to enjoy your tub.  It's not there to create more stress, it's there to take it away!

[Chas]

Read http://www.whatsthebest-hottub.com/cgi-bin/yabb/YaBB.pl?num=1213274466

I think most folks overthink the spa care.

 8-)

[canecreek]

Thanks folks, and Chas, I'm taking that advice.   Folks who PM'd me: sorry no replies possible til I reach 5 posts.

I think I just have to find a way to dissolve these bromine tablets faster? Crush them maybe.  I'll get it.

[zroger73]

Wow. What a thread! I am not a chemist and cannot even begin to dispute or take sides over the best water treatment method. However, almost one year ago I became a first-time owner and hot tub newbie. Out of fear and conflicting information from various sources, I decided to follow the water maintenance suggestions straight out of the owner's manual. One year and three water changes later my maintenance costs have averaged $10.00 per month, the water stays fresh and clean, and no one has came down with an infection.

MY personal opinion is that if common household bleach was "better", then Hot Spring would sell you a gallon of re-branded Chlorox for $49.99. Also, I don't mind paying $10.00 per month for chemicals and cartridges considering I spent $8,000.00 on an agitating hot water bowl.

I understand this thread seems more oriented towards water sanitation than chemical costs, but... If household bleach was the magical answer for cheap, effective water sanitation, then why isn't it found in commercial applications and why haven't the manufacturers marketed it as an additional product line for yet more profit?

With all the liability involved with products these days, I think I'll stick with the manufacturer's recommendations until I get my chemical engineering degree (never). If I use bleach and my skin falls off and my hot tub explodes, then it's my problem. If I use dichlor and my skin falls off and my hot tub explodes, then the manufacturer is subject to liability because the manual specifically states dichlor is recommended and approved for reliability and sanitation.

[In Canada eh]

With all the liability involved with products these days, I think I'll stick with the manufacturer's recommendations until I get my chemical engineering degree (never). If I use bleach and my skin falls off and my hot tub explodes, then it's my problem. If I use dichlor and my skin falls off and my hot tub explodes, then the manufacturer is subject to liability because the manual specifically states dichlor is recommended and approved for reliability and sanitation.

I'm really trying to stay out of this thread, but I did want to say that Roger makes a very good point

[Chas]

MY personal opinion is that if common household bleach was "better", then Hot Spring would sell you a gallon of re-branded Chlorox for $49.99. Also, I don't mind paying $10.00 per month for chemicals and cartridges considering I spent $8,000.00 on an agitating hot water bowl.

.....If I use dichlor and my skin falls off and my hot tub explodes, then the manufacturer is subject to liability because the manual specifically states dichlor is recommended and approved for reliability and sanitation.

Very good logic, very well stated.

 8-)

[Tman122]

4 pages about dichlor not good. And guys like me and Chas and thousands of others been using it for 20 or more years with not one single problem, clean sanitized water always. What's all the hub-bub?

[chem geek]

There were 36 incidents of hot tub itch, rash, bumps, or hot tub lung reported on another forum over around 3-1/2 years (I stopped keeping track months ago and there have been more reported since).  Some were confirmed by doctors with swabs as Pseudomonas aeruginosa (most were just diagnosed visually) while the hot tub lung was confirmed as Mycobacterium avium.  Most incidents were due to low or no sanitizer including use of alternative systems.  8 of the incidents were with Dichlor-only use and most of these had problems only after around 2 or more months and were generally tubs used daily with Dichlor added after each soak in sufficient amounts to register at least some FC before the next soak -- these people were doing everything right, as far as they knew.

That is the ONLY reason I got interested in seeing if perhaps it might be better to have more consistent disinfection with initial Dichlor and then switching to bleach before the CYA built up too much.  I've communicated with the people who have had these problems and it's not something to be flip about.  Unfortunately, Dichlor-then-bleach has downsides (that can be mitigated) but is more complicated for some people.  On the plus side, those that do manage it find their water to either last longer or to have better quality at the point when they do change it.

I am NOT pushing this method, but I don't think one should ignore the problems that have been reported.  The other ways of avoiding the problems would be to use N2 or similar metal ion system along with Dichlor or MPS (since there were far fewer incidents with N2) or one could change the water more frequently, possibly after 2 months if the tub is used daily (or, of course, one could use bromine or Baqua/biguanide/PHMB instead but need to maintain appropriate sanitizer levels in any case).  Obviously the odds of having a problem are low to begin with, but it's a spectrum of risk and I don't think these people are just making this stuff up.

Richard

[Nitro]

Every time you add 10 ppm FC using Dichlor, you add 9 ppm CYA. Your Active Chlorine (AC) is FC/CYA. That means your AC (Effective Sanitation) drops by 1/10th every time your add 11 ppm FC to your tub using Dichlor.




Picture this: It's one week after filling your tub, and you're using only Dichlor as a sanitizer. Your CYA is 20 ppm. Your FC is 3-6 ppm, and the water is pristine. A month later, assuming your FC is 3-6 ppm, it will only be as effective as if it were 0.5-1 ppm the first week. After two months it will only be as effective as if it were 0.25-0.5. After three months your effective sanitation level (AC) is only as effective as if you had 0.15-0.3 the first week.

Would you keep your FC at 0.15-0.3 ppm one week after a refill?




The point is, the effectiveness of the FC (sanitizer i.e. Dichlor) continuously drops as you add more Dichlor to the tub. After three months, the only way to get that same AC (Effective Sanitation) you once had the first week, is to added 50-100 ppm FC. Not too practical!

Bottom Line: the more Dichlor you use, the less effective it becomes.

[Markus]

I personally use the “add a teaspoon of dichlor method” after every use. I’m very good about maintaining water chemistry. My water is always crystal clear. 2 ½  years after owning it…I developed small itchy bumps on my arms and my wife has since developed very itchy bumpy skin. My problem went away…hers hasn’t. I never used Nature 2…but I think I’ll try that next after a thorough cleaning of the spa. If that doesn’t work then I’ll try the bleach method.

For those of you who aren’t having problems…I probably wouldn’t change a thing. But for those of us who are…the bleach theory might be something to experiment with.

…just my thoughts.

[chem geek]

I personally use the “add a teaspoon of dichlor method” after every use. I’m very good about maintaining water chemistry. My water is always crystal clear. 2 ½  years after owning it…I developed small itchy bumps on my arms and my wife has since developed very itchy bumpy skin. My problem went away…hers hasn’t. I never used Nature 2…but I think I’ll try that next after a thorough cleaning of the spa. If that doesn’t work then I’ll try the bleach method.

If you are only adding just one teaspoon of Dichlor after a soak, then you are very likely not using nearly enough chlorine to oxidize your bather waste unless you are also adding another oxidizer such as non-chlorine shock (MPS) or have an ozonator.  At hot temps (100-104F) it takes around 3-1/2 teaspoons of Dichlor for every person-hour of soaking.  One teaspoon would only be good for around 15 minutes of one person soaking (unless you don't sweat as much as average).  If both you and your wife soak for 20 minutes, then you would need around 2-1/3 teaspoon of Dichlor after each soak.

Did you test your chlorine level before your next soak to see if there was measurable (about 1 ppm FC) chlorine?  If not, then you probably had near zero chlorine in the water for long periods of time because whatever chlorine you added probably got consumed by the ammonia and urea in your sweat and urine very quickly.  Once you get behind, you don't catch up unless you shock the tub with enough oxidizer.  Most people do not use enough oxidizer unless they are measuring their sanitizer levels to make sure they still have a residual the next day before they soak again.

Richard

[hottubdan]

If you are only adding just one teaspoon of Dichlor after a soak, then you are very likely not using nearly enough chlorine to oxidize your bather waste unless you are also adding another oxidizer such as non-chlorine shock (MPS) or have an ozonator.  At hot temps (100-104F) it takes around 3-1/2 teaspoons of Dichlor for every person-hour of soaking.  One teaspoon would only be good for around 15 minutes of one person soaking (unless you don't sweat as much as average).  If both you and your wife soak for 20 minutes, then you would need around 2-1/3 teaspoon of Dichlor after each soak.

Did you test your chlorine level before your next soak to see if there was measurable (about 1 ppm FC) chlorine?  If not, then you probably had near zero chlorine in the water for long periods of time because whatever chlorine you added probably got consumed by the ammonia and urea in your sweat and urine very quickly.  Once you get behind, you don't catch up unless you shock the tub with enough oxidizer.  Most people do not use enough oxidizer unless they are measuring their sanitizer levels to make sure they still have a residual the next day before they soak again.

Richard

Richard,

You don't address gallons here.  Is that a factor.  Also in this statement you are addressing oxidation, not sanitation.  Is the 1 teaspoon enough for sanitation?  Then with weekly oxidation (MPS or chlorine) should Markus be doing ok?

[chem geek]

Richard,

You don't address gallons here.  Is that a factor.  Also in this statement you are addressing oxidation, not sanitation.  Is the 1 teaspoon enough for sanitation?  Then with weekly oxidation (MPS or chlorine) should Markus be doing ok?

I specifically quoted the amount of Dichlor that needs to be used rather than quote an FC that is needed because the size of the tub in gallons is not a factor when it comes to the amount of oxidizer physical amount (not concentration in the water) required to get rid of bather waste.  The rough "rule" is an over-simplification because it does combine the amount needed for oxidation of bather waste with a smaller amount of normal loss over a 24-hour period, but the bulk of chlorine usage is for oxidation.

As for sanitation, that is why I asked whether the Free Chlorine (FC) was at a measurable level (1 ppm or more) just before the next soak.  If it was, then there was at least some chlorine left available for sanitation.  Remember that chlorine for oxidation and chlorine for sanitation are the same chlorine.  So if there is bather waste, then the chlorine will mostly get used up oxidizing such waste and if there is more waste than chlorine, then the chlorine level will get to zero and there will be no sanitation.  This is why regular testing, at least early one before you get a feel for your usage pattern, is very important.

One can substitute MPS for chlorine as an oxidizer.  It takes about twice as much MPS by volume as Dichlor for the same effect so it takes about 7 teaspoons of MPS per person-hour of soaking and this is all equivalent to around 5 fluid ounces of 6% bleach.  The weekly oxidation would let one "catch up" if one fell behind, but the problem is that during the time you are "behind" you are getting no sanitation.  If the shocking were to let you have excess oxidizer in the water so you get "ahead", then that would work to allow for chlorine to sanitize, but MPS doesn't last that long (probably not more than a couple of days at spa temps).  Basically, you can't get away with small daily doses and a larger weekly shock.  It's better to use enough oxidizer daily, assuming you are soaking every day.

It's tricky to use MPS in place of chlorine because both measure in the chlorine test, though MPS usually mostly shows up as Combined Chlorine (CC) though at high levels or soon after dosing it can show up as Free Chlorine (FC).  If you have Nature2 or other metal ion system with silver, then MPS becomes an effective sanitizer so you can use mostly MPS and just use chlorine as a shock as needed if the water gets dull (that's the "low chlorine" approach with N2).

Remember that most of the hot tub itch/rash... reports were due to very low or zero sanitizer levels and this was mostly due to not using enough oxidizer to get rid of bather waste.  In many cases it is because people did not scale the amount of Dichor (or other oxidizer) relative to their heavier tub usage with more than one person or with one hour soaks.  The easy way to know if you are using enough is simply to test the FC level just before soaking -- if it's zero or near-zero, you aren't adding enough oxidizer after the soak.

There is a separate problem if you are using mostly Dichlor in that over months when the CYA builds up this makes the chlorine take longer to oxidize the bather waste.  Depending on usage, it can get to the point where you get behind and begin measuring Combined Chlorine (CC) even before your next soak.  The water can start to look a little less clear and seem sluggish.  This is NOT just due to time or TDS, but is mostly due to the buildup of CYA making chlorine a slower oxidizer.  With Dichlor-then-bleach, this doesn't happen so the water lasts longer, though eventually the buildup of non-oxidizable chemicals (and salt, though it takes even longer for that to become an issue) does eventually occur so a water change is still needed.

Richard

[Markus]

Let me correct that statement...I add a teaspoon of dichlor for each of us. We generally stay in the tub approximately 15 minutes each night. I do monitor the FC and it is normally around 1 or 2 PPM before we enter the spa. I shock once a week with MPS and I do have an ozonator. My wife is convinced that the tub is contaminated. Tonight I Spa Purged the tub and rinsed everything down and refilled. I also cleaned the filters with a filter chemical solution.

We'll see what happens when she tries it again!