Dichlor (The Dirty Little Secret)

[chem geek]

Thanks for the clarification and sorry I misunderstood.  OK, so you are using enough oxidizer and you are maintaining a residual sanitizer (except possibly at some point during the 15 minute soak itself).  That's good.  You didn't say the size of your tub, but let me assume that it's a pretty common 350 gallons.  So 2 teaspoons (1 for each of you) of Dichlor in 350 gallons adds 4.0 ppm FC and 3.6 ppm CYA to the tub every night.  That's an increase in CYA of 108 ppm per month.

So did the itchy bumpy skin initially develop within the first month after a fresh refill or did it occur after some months of use, and if the latter, after how many months?

[Markus]

We are actually about to start the experiment. I just replaced the water and I will monitor how long it'll take for her itchy skin to come back.

[Spalady]

Let me just start by saying that after 30 years in this industry, I have never seen so many complicated responses...And if this is what potential customers think of water chemistry we might just as well start selling something simple like nuclear energy!
I know some of you love to chat up the chemistry knowledge, but so far this seems to be people who don't sell spas or have to deal with customers trying to just keep it understandable. (Ok well I have only had to deal with about 15,000 customers but hey what do I know?)

In our experience 2 things can cause a rash:
1. pH/Alkalinity not in balance
2. Sanitation too low

Vanguard: you have an ozone system right? Please make sure it is working! When did you last clean the venturi or have it serviced?
A little sanitation is fine, but once a week... make sure you hit a 10PPM level on your test strips when balancing the water so that you actually do a shock treatment. WE use enhanced shock or lithium hypochlorite as a shock agent.
Others here will recommend other products. I really don't care. The bottom line is IF you want to keep it simple, you have the perfect spa to accomplish that.
Ok, I expect a lot of attacks on this being too simple, so I will await the responses..
And as far as the 'costs' of Lithium or Enhanced vs bleach, what about the cost of a doctor because you couldn't figure it out or the time you will spend? Customers have paid $5 - 10K for  great products to enhance their lives. $20 in chemicals that are easy to use, available through legitimate dealers with knowledge is a small price to pay to take care of their investments.

[Chas]

Ditto.


 8-)

[chem geek]

WE use enhanced shock or lithium hypochlorite as a shock agent.

Lithium hypochlorite produces identical chlorine as sodium hypochlorite (bleach) and also adds the same amount of extra salt and also is high in pH upon addition.  Unlike Dichlor, it does not increase Cyanuric Acid (CYA).  The only difference, other than being solid granular and more concentrated (by weight or volume) vs. liquid, is that it is 5-7 times more expensive than bleach for the same Free Chlorine (FC) level.  See this link for lithium hypochlorite (pH 11 for 1% solution) and this link for Clorox Regular bleach (pH 11.4).  Is it really that hard to explain that 1 ounce (2 tablespoons) of lithium hypochlorite is equivalent to 5 fluid ounces of 6% bleach (unscented Clorox Regular being the best since it has the least amount of "excess lye" in it)?

So it is good that you are recommending it for shocking since it doesn't increase CYA as Dichlor does.

As I posted, most of the 36 incidents of itch/rash were too low or no sanitizer, which is consistent with what you have seen.  The 8 incidents of Dichlor-only use had maintained sanitizer levels and balanced pH and TA; there were more than 8 Dichlor-only incidents, but if they didn't use enough Dichlor to have measurable FC before the soak, then they are not included in these 8 incidents and instead counted as "low or no sanitizer".  Are you saying that out of 15,000 customers you have had none that had rash/itch if they had measurable FC before each soak and a reasonable pH and TA?  Do all or most of your customers have ozonators or Nature2 or other systems in addition to Dichlor as the primary (daily) sanitizer?

Richard

[Vinny]

People are forgetting that some people are allergic to MPS.

Something else I would like to say about sanitation - we hear about "bad" things because bad news travels faster than good news AND people tend to seek advice when they are having trouble. In my limited experience on 2 forums I have "met" 100 people or so.  Based on the number of people with problems there is about a 10 to 25 % base of people who have problems - a high number. But there are more than 100 or so people who own spas and they do not come in to say HI! We will only get those people who have problems, get them solved and go away. We also get people who were given wrong advice (some even from forums) and are looking for help. Based on the knowledge that if all total the spa industry sells 1,000 tubs - that percentage goes to 1 to 2.5%; if 10,000 that number goes to 0.1 to 0.25% - very low numbers.

I think it is unwise to take a captive audience, whose sole purpose is to help people with their problems (that is what we try to do) and say look at the problems that we have seen. Since most of the world can use a computer finding a place for your problem is so easy. Want to grow grass; kill bugs or learn about stock trading - go on the internet! I have owned my spa for 4 years and other than stupidity on my part and letting the spa go (other than for experimenting with things) I have not had any problems with my dichlor only routine except a time when both my boys got ear infections from dunking their heads under water - solution to that is to not dunk their heads.

A fair assessment is to take a cross section of people (can't be done on the internet) that aren't seeking advice. How many people out there own a Chrysler or Pontiac ... I own 2 Hyundai's, does that mean my cars are better?

[just ducky]

Let me just start by saying that after 30 years in this industry, I have never seen so many complicated responses...And if this is what potential customers think of water chemistry we might just as well start selling something simple like nuclear energy! ....

As a newbie to this game, thank you.  This reminds me of a lot of many other subjects, which you can make as complicated as you want.  It's like we're all sitting around a table in the local coffee shop...everyone has an opinion.

I have to admit, I've quit reading this, and posts like it.  If I didn't, I'd be completely petrified to use my new tub.  I bought from a reputable dealer, who has been more than willing to help.  And several dealers on this site have given me their thoughts too.  But I have to say, after the first week or so of getting used to things, I've found it very easy to maintain a well-balanced tub.  Two months, and quite a few different people tubbing, and no itches or other nasties so far...knock on plastic!  

Common sense is one thing...but when do you stop?  This is only a hot tub for gosh sake!

[chem geek]

I think it is unwise to take a captive audience, whose sole purpose is to help people with their problems (that is what we try to do) and say look at the problems that we have seen.

I only referred to the incidents in defense when others claim there are NO problems or that they are ONLY due to low sanitizer (or TA, etc.).  I totally agree with you that for most hot tub users Dichlor-only works out fine and I've said that before in some posts of mine.  I am not saying people should switch from that (I'm not saying the same things Nitro is -- he's more gun-ho about this).  But I am saying there is clearly known science that relates to both disinfection and oxidation (water quality) so there IS an alternative to make this more consistent.

This info is NOT meant to scare anyone, but there IS a spectrum of risk.  If you use a metal ion system in addition to the chlorine regimen you are at lower risk and certainly have more "insurance" in case the chlorine level gets too low and not everyone is so diligent to maintain chlorine levels.  It's not as clear as to whether Dichlor-only vs. Dichlor-then-bleach will have a noticeable lowering of risk since it's too early to tell, but the improvement in water quality after months is noticed by most who use the approach.

I'm sorry Nitro was so bold on here implying "this is the best" or "this is the only way that should be done" since it detracts from simply talking about alternative approaches.

I've also personally communicated offline with many of the people who had incidents and some of these things are quite serious, including hot tub lung and one case of Legionnaires disease (this latter case almost killed the person, but was due to not properly sanitizing a hotel room spa).  So I find it insulting to them to discount real problems a small number of people have had.

One final note is that some number of rash/itch reports were apparently due to things like the jets being too strong or those with more sensitive skin, so it's not just bacterial nor chemical sources of irritation, but physical ones as well.  So it's great that dealers like Spalady and Chas are able to get every single one of their customers properly tuned in their spas with correct jet flows and proper sanitation.  That's why I asked whether they mostly or always have ozonators or other systems because maybe that helps and would be useful for most to know -- I'm on for whatever works.

Richard

[just ducky]

...One final note is that some number of rash/itch reports were apparently due to things like the jets being too strong or those with more sensitive skin, so it's not just bacterial nor chemical sources of irritation, but physical ones as well....Richard

Richard,

I agree with this as well.  As a pretty new tub owner, I can tell you that my skin can take, and actually enjoy, a lot more pressure from a jet than my wife.  What I find very relaxing after a particularly stressful day is getting in one of the corners that really "beats me up", and I open all jets and air, and let 'er rip!  My wife would probably be screaming in pain, because they do a really good job!  She's just a lot more sensitive than I am.  This is one of the reasons that I'm so glad I listened to many of you before I bought, and did several wet tests to actually FEEL the jets work.  We're two months into this tub, and we couldn't be happier because it has enough options in jets/pumps/air that we can both be happy at the same time.

So yes, there are other things to consider.

[Tman122]

I've been dumping in a couple teaspoons of dichlor after use, shocking with a couple tablespoons of dichlor for a shock or a few ozs. of MPS after 8-10 soaks for 10-15 years!! Always had crisp clear water. Never had a bacteria problem. Drained every 3-4 sometimes 5 months depending on how much use. Imagine my suprise to read this thread and find out it wasn't right!!! Now what do I do?

[Vinny]

Richard,

I wasn't pointing directly at you; if you felt I was - I apologize. What I was trying to say is that we all see the people who are seeking help on these forums and not seeing a lot of the people who don't need help. I repair medical equipment and you have to see how many times people, professionals, don't know what the heck they are talking about or how to use what they touch every day. I worked on something today that was "broken" and the connector was in wrong! It even had letters on it that were upside down when it was installed wrong. :-?

I have a great respect for your knowledge as I hated chemistry in college! I also know you are not saying what Nitro is saying - I learned that a while ago from a conversation I had with you on one of the pool websites that you frequent. If bleach could be in powder form I certainly would use it all the time once my CYA gets to 25 or 30 but like I said dichlor is so easy to use. I think the bleach = great; everything else = bad is too pervasive on the forums that I had those conversations with you that I no longer go to them. It's a shame as I learned a lot from the originator of the first forum and also from you. I don't know Nitro but it sounds like he subscribes to that idea as well.

I disagree with the N2 or Frog people and the ozone effect. They do work somewhat but silver works slowly so I question how effective silver is in a spa situation and spa/pool ozonators can only inject so much ozone with air being at 21% O2. With my own tub, N2/frog and ozonator (which is a very small sample) I have not seen either work well. It could be my water, my tub design, my ozonator or me. My experimentation on my own tub showed that N2/frog and ozone give me 1 extra day of clear water (4 days vs 3) but clear water doesn't equal clean tub. I've tried the N2/frog on 3 separate occasions. I can actually get clear water sometimes just from dichlor for 4 or 5 days as well.

Just wanted to clear my post!

Vinny

[chem geek]

I've been dumping in a couple teaspoons of dichlor after use, shocking with a couple tablespoons of dichlor for a shock or a few ozs. of MPS after 8-10 soaks for 10-15 years!! Always had crisp clear water. Never had a bacteria problem. Drained every 3-4 sometimes 5 months depending on how much use. Imagine my suprise to read this thread and find out it wasn't right!!! Now what do I do?

Don't change anything.  What is being discussed is something affecting a smaller number of people.  Just out of curiosity, do you have an ozonator or are you using Nature2/Frog or other metal ion system?  How often do you soak each week (number of soaks, how many people, how long per soak)?

[chem geek]

Richard,
I disagree with the N2 or Frog people and the ozone effect. They do work somewhat but silver works slowly so I question how effective silver is in a spa situation and spa/pool ozonators can only inject so much ozone with air being at 21% O2. With my own tub, N2/frog and ozonator (which is a very small sample) I have not seen either work well. It could be my water, my tub design, my ozonator or me. My experimentation on my own tub showed that N2/frog and ozone give me 1 extra day of clear water (4 days vs 3) but clear water doesn't equal clean tub. I've tried the N2/frog on 3 separate occasions. I can actually get clear water sometimes just from dichlor for 4 or 5 days as well.

Vinny, not to worry.  I don't strongly recommend the dichlor-then-bleach unless people are specifically having problems with sanitation and are already dosing properly or if they really want to try it with its caveats.  On the other hand, I'm not opposed to anyone using it, but those with ozonators need to be particularly careful due to the extra aeration from the ozonator so they have to watch the pH rise issue much more carefully (and control TA and use borates, as needed).  I agree that people tend to seek out help on forums mostly when things are going badly or when they are new and have questions, but a lot of people don't go to the forums at all so if there are common reports on a forum, odds are there are a lot of people in absolute numbers, if not in percentage, that are having similar problems.

At first, I too was skeptical about silver since it is a slower killer, but it still kills quickly enough to prevent uncontrolled bacteria growth though not fast enough to prevent person-to-person transmission and it's not great against viruses.  I did find scientific support for silver with non-chlorine shock (MPS) described here which explains how N2 could have passed EPA registration for their "low chlorine" recipe which primarily uses MPS.  This combination ONLY works at hot spa temperatures, so would not work in pools.  As for the bacteria that causes hot tub itch, I'm only assuming that it's helpful given the relative paucity of reports of trouble with those using N2 (though there were a few reports; with Dichlor after 1-2 months).

I've now looked back to see who was using an ozonator (that we know of) and there are reports of problems with those using an ozonator, but less than those without.  But without knowing the sample size of how many people have spas with ozonators, how many with N2, etc., it's hard to draw any solid conclusions about such prevention.

What does seem to be known about ozonators from people's reports (not just on itch/rash, but generally) is that 1) they vary in terms of using more or less chlorine and 2) they can fail yet the air injection bubbles have people think they are still working.  It seems that the ozonator works better in higher bather load conditions since it oxidizes more bather waste so chlorine doesn't have to.  Under lower bather load conditions, it can end up oxidizing chlorine itself and/or making it outgas faster, thus using it up more quickly.

I wouldn't expect N2 to help keep water that clear since it's not an oxidizer -- it would just prevent bacterial growth (OK if tub not in use, but with bather waste the water would get dull without an oxidizer).  I would, however, expect a working ozonator to keep the water clear so am surprised at your situation -- most posts I've seen report ozonators keeping water clear -- at least when they are working.  Do you know if your system is Corona Discharge (CD) or Ultraviolet (UV)?

Richard

[zroger73]

I sorta agree with the poster that said they weren't too interested in reading posts like these. I keep reading just out of curiosity. As I stated before, I'm no chemist and I'm at the mercy of my nose, eyes, less-than-perfect test strips, and owner's manual to maintain my water chemistry. My tub came with ozone. I replace the Nature2 cartridge at each refill. I use only a weekly dichlor shock and a teaspoon or two before and/or after each use (depending on how long it's been since used, bather load, etc.). I've had dozens of people use my hot tub anywhere form 30 minutes to several hours. Several completely submerged themselves (I'm not a big fan of "diving" in a hot tub). I change my water every 4 months at which time I also rinse off my filters. The spa is always covered when not in use. I've yet to have anyone experience even the slightest infection or allergy.

My dealer has told me some of the "horror" stories he's seen. I believe every one of them. I can only imagine owners who assume the hot tub will magically take care of itself and who believe maintenance is overrated. I can also imagine those who dump gallons of unnecessary chemicals out of fear. Gotta find a happy medium!

[Vanguard]

I've been dumping in a couple teaspoons of dichlor after use, shocking with a couple tablespoons of dichlor for a shock or a few ozs. of MPS after 8-10 soaks for 10-15 years!! Always had crisp clear water. Never had a bacteria problem. Drained every 3-4 sometimes 5 months depending on how much use. Imagine my suprise to read this thread and find out it wasn't right!!! Now what do I do?

That was funny.  I just read through this thing today.  Holy Crap!!  All this over how to take care of a hot tub?  

I've found that my Dichlor, Ozone, N2, and MPS has worked just fine and dandy.  

I think I'll keep on doing it that way.  Plus, my little plastic bottles have directions on them so when I forget, I can just read it again.  I checked my bleach in my laundry room...there are no directions for how much to use in a hot tub.  Since I don't really care if I remember how much to put in every time, I like having the directions on the bottle.