Dichlor (The Dirty Little Secret)

[Nitro]

If you are using Granulated Chlorine (aka Dichlor) to sanitize your hot tub, this is a must read!

Chem Geek has written an excellent detailed explanation about the effects of using Dichlor in your hot tub HERE. He is probably the leading researcher on this subject. I'll try to summarize it here in a new thread, because I don't want his info to get lost in an off topic thread where few people will see it.

Dichlor essentially has two ingredients, Chlorine and Cyanuric Acid (CYA). Almost everyone knows about Chlorine, but few people know about CYA. CYA is used in outdoor swimming pools to limit the breakdown of Chlorine from UV rays. However, it also acts as a Chlorine stabilizer. Basically, it limits the effectiveness of Chlorine, while allowing it to last longer. Think of Chlorine as being a wildfire, and CYA being a water hose. CYA in a sense controls the Chlorine from burning everything up (i.e. you and your tub).

Therefore, CYA is a GOOD thing to have in every hot tub and pool (including indoor). The problem comes when there is too much. If there is too much CYA in your tub it will limit the Sanitation (burn) rate too much, allowing certain types of bacteria to grow and form biofilms, namely Pseudomonas Aeruginosa (Hot Tub Itch).

Here are some details:

For every 10 ppm FC you add to your tub using Dichlor, you add 9 ppm CYA. Active Chlorine is a measure of how effective the Chlorine in your tub can kill bugs, and oxidize waste. Active Chlorine is estimated by the ratio FC/CYA. As CYA increases, Active Chlorine decreases (assuming FC remains at normal levels between 1-10). This means every time you add ~11 ppm FC (10 ppm CYA), you drop the Active Chlorine by 1/10th.

Let's look at some real numbers. Assume a 350 gal tub with an average of 4 ppm FC added everyday using Dichlor, which is typical. After the first week you will have 25 ppm CYA. After the first month you will have ~100 ppm CYA. That means your Active Chlorine is FOUR times less after a month than it was the first week. So after a month when you soak in your tub with 4 ppm FC, that's equivalent to 1 ppm the end of the first week. After the second month (CYA = 200 ppm), 4 ppm FC is equivalent to 0.5 ppm. Get the picture?

You might be asking why are they selling us Dichlor which contains CYA. The main reason is that you do need some CYA in your tub. If you have no CYA in your tub the chlorine would be way too strong causing damage to you and the tub. If you had 4 ppm FC in the tub with no CYA, that would be equivalent to ~120 ppm FC with CYA at 30 ppm. That would be a level used in a Decontamination procedure. Not safe for you, or the tub. Some manufactures will even void the warrantee if they find out you were using Chlorine with no CYA. So to try to keep customers from destroying their tubs and themselves, the industry created a product (Dichlor) with Chlorine and a stabilizer (CYA). However, as we have seen from the facts above, this is not the best solution. As CYA increases in your hot tub, the risk of getting ill (i.e. Hot Tub Itch), and/or having water problems (cloudy water etc.) is much greater.

Some may say they have been using Dichlor for years, and never had a problem. Or, if you change the water evey 2-3 months, you won't have a problem. I say, why risk it, if there's a better solution? If you are using Dichlor in your tub now, a better solution is the Dichlor/Bleach method, pioneered by (you guest it) Chem Geek. All you do is use Dichlor for the first week to build up CYA to 20-30 ppm, then switch to Regular Clorox Unscented Bleach. Bleach has no CYA, so your Active Chlorine will remain the same up until you drain the tub. Other advantages of using Bleach are it's cheap and easy to get. The water will last about twice as long. The only other difference is you need to keep your TA lower (50-60 ppm), and are recommend to add Borates (which actually make the water feel and smell better). If you would like to learn more about this method, check it out HERE.

Lastly, there is no guarantee with this, or any method. All we can do is lower the risk.

[Jacuzzi Jim]

 While that's all real nice, we are not selling Clorox bleach out of our store, I know a lot  (like us) retailers do quite well on chemical sales and by telling a customer, oh just use bleach is not going to fly with us.

  FWIW I find all this info great reading, too much reading, but it is still informative and a great refresher for me.




    

[Nitro]

While that's all real nice, we are not selling Clorox bleach out of our store, I know a lot  (like us) retailers do quite well on chemical sales and by telling a customer, oh just use bleach is not going to fly with us.

Thank you for mentioning the other reason they sell us Dichlor, $$$.

Fortunately I have no interest in selling chemicals (or anything), so I'm free to tell the whole story.

[Spalady]

Again, informative but too much to call easy maintenance.
Fortunately we sell a spa with a great ozonator system and with the use of a hypochlorite (like Enhanced or Litihium Hypochlorite) we can keep our maintenance very simple and user friendly.
I hate seeing customers using liquid chlorine if for no other reason that splash back, spillage on the surface which can bleach and the inconsistencies of concentration depending on where they purchase it.

It is also important to note that customers coming to stores where professionals work can get support, feedback and answers to questions that employees at the local drug store can not offer. More customers are confused by non-professionals giving opinions, anecdotal  or incorrect information. Spa retailers have access to data provided by chemical manufacturers and chemists that they can turn to for answers to questions on water care.  Plus, I love seeing my customers and checking in with them when they stop by for products!

[Nitro]

Again, informative but too much to call easy maintenance.

The Dichlor/Bleach method is very easy maintenance. Anyone who thinks otherwise has never tried it. It would be even easier if the Industry would produce a Starter Pack containing Cyanuric Acid and Boric Acid that we add to our tub on a fresh fill. Then they could even sell Bleach (but call it Sodium Hypochlorite so nobody knows it's really Bleach) at a higher price. At least it would be safer than using only Dichlor.

Fortunately we sell a spa with a great ozonator system and with the use of a hypochlorite (like Enhanced or Litihium Hypochlorite) we can keep our maintenance very simple and user friendly.

Litihium Hypochlorite is way more expensive than Bleach (almost 20 TIMES). No Thanks! HERE is link to price comparison.

I hate seeing customers using liquid chlorine if for no other reason that splash back, spillage on the surface which can bleach and the inconsistencies of concentration depending on where they purchase it.

Most people are responsible enough to use bleach. Folks have been using it for years. My mother used it for years, on my socks and underwear. It's a lot safer to handle than say, Muratic Acid. Also, Reqular Unscented Clorox 6% Bleach is recommended, but it really doesn't matter the concentration. If they are measuring their FC (like they need to), they will end up using more or less.

It is also important to note that customers coming to stores where professionals work can get support, feedback and answers to questions that employees at the local drug store can not offer. More customers are confused by non-professionals giving opinions, anecdotal  or incorrect information. Spa retailers have access to data provided by chemical manufacturers and chemists that they can turn to for answers to questions on water care.

Not all professionals are as nice, informative and fun to be around as you Spalady. Some are downright nasty, others are uninformed and others just don't care except for selling their high priced chemicals. Anybody that sells their customers "Alk Up" at a higher price than regular Baking Soda is not someone I would trust giving me advice on maintaining my water.

Dispite what some think, you can get far better (honest) advice on the Internet than from most of the "professionals" trying to sell you products at high prices, or that you don't need. After all Spalady, you are on the Internet.

Plus, I love seeing my customers and checking in with them when they stop by for products!

$$$

[hottubdan]

Dispite what some think, you can get far better (honest) advice on the Internet than from most of the "professionals" trying to sell you products at high prices, or that you don't need.

And you can also get bad and dishonest advice on the net.  

And using bleach in the laundry is not the same as using it in a hot tub or swimming pool.

By the way, what is the other 94%?  

[Chas]

By the way, what is the other 94%?  

THAT is an excellent question.

I have used the simple system for years - in my spa and thousands of my customers:

• Dichlor as you exit,
• Keep the water in balance,
• Change every four months.

This works best if you have a good filtration system and a working ozonator.

 8-)

[Nitro]

And you can also get bad and dishonest advice on the net.

But at least you get BOTH sides of the argument, unlike in a dealer/retail shop, who's main goal is to sell you something.

And using bleach in the laundry is not the same as using it in a hot tub or swimming pool.

Why not? You pour it into a measuring cup, and pour it into the tub. It's easier than drinking a hot cup of coffee. Anyone who tells you otherwise has never done it, or is misleading you. The "bleach is bad" argument doesn't hold water. (pardon the pun)

By the way, what is the other 94%?

Mostly water and a little salt.

[Nitro]

THAT is an excellent question.

I have used the simple system for years - in my spa and thousands of my customers:

• Dichlor as you exit,
• Keep the water in balance,
• Change every four months.

This works best if you have a good filtration system and a working ozonator.
 8-)

Four months using Dichlor, with a high bather load such as 50 ppm FC per week. That would be ~720 ppm CYA. I find it hard to believe out of your thousands of customers, none of them had water problems with those instructions.

HERE are some cases who did have problems. Dichlor use after one month is at the top of the list. And that's just from an informal Internet study. Imagine all the cases that go un-reported.

I bet if you told your customers they could use regular household bleach from the grocery store that's cheaper and safer, they would.

[chem geek]

Dichlor has been used by many, many spa users without problems.  The approach of adding it after a soak was called the Vermont/Vermonter/Northman method.  The lower sanitation levels at higher CYA levels wasn't understood since it's not widely published and is disputed by the chlorinated cyanurate manufacturers using arguments such as 1) it hasn't been proven that the slower kill times happen in "real pools" or 2) no study has shown outbreaks correlated with CYA level.  Of course, this ignores the numerous scientific studies in the lab and experiments and theory described in this post.  The two pool studies (that the industry funded) showed that uncontrolled bacterial growth in pools was mostly prevented with very low amounts of chlorine that were so low that CYA could not be isolated as a factor -- and they didn't look at kill times nor at hypochlorous acid concentration.  The reason no study has shown correlation of outbreaks with CYA is that CYA isn't looked at in most outbreak reports and most cases outbreaks are due to no chlorine -- but virtually all respiratory and ocular problems are associated with indoor pools and most indoor pools do not use CYA (of course, indoor pools have worse air circulation and don't have exposure to sunlight, which are additional factors, but not having any CYA in the water makes chlorine "too strong").

Just because I collected info on a hot tub site for hot tub itch/rash/lung does not prove anything.  It's just a collection of empirical evidence giving hints or suggestions that when combined with chemical theory known since at least 1974 plus lab studies through the 70's and 80's suggests that having a more stable Cyanuric Acid (CYA) level would be a good idea.  Hence, the Dichlor-then-bleach method.

Like many things in life, there are pros and cons with every choice.  Dichlor-then-bleach requires some initial effort to control the pH via lowering the TA and usually using Borates.  It's way too early to tell if it's a better method for most people.  It might be that using N2 with Dichlor-only or MPS is good enough and safe enough.  I will say that without N2 it does look like Dichlor-only is a bit riskier.  On the plus side with Dichlor-then-bleach, it looks like you can go about twice as long before needing to change the water and it's less expensive.

Finally, as I have told/posted to you and others, I am not a researcher or scientist.  I am just a pool owner with a strong interest in pool/spa water chemistry.  That's why I always link to sources and info that people can check and verify or draw their own conclusions.  I have communicated with various organizations including those involved with standards such as APSP-11, CDC MAHC, NSF International, and I've met several of the key players in person at a conference, but I don't believe I'm making much headway with regard to the chlorine/CYA relationship issue and the inconsistency of the current rules using CYA in outdoor pools and not in indoor pools or commercial/public spas in spite of the order-of-magnitude differences in disinfection/oxidation rates (essentially, indoor pools at typical 1-2 ppm FC with no CYA are over-chlorinated and should have a small amount of CYA) including the implications of breakpoint chlorination models that show order-of-magnitude greater very irritating nitrogen trichloride production when CYA is not used to moderate chlorine's effective strength.  No one is disputing the science (except with the arguments noted above), but they don't want to change the regs either.

Richard

[Vanguard]

Actually, a huge majority of pool owners in the southeast use bleach for their preference in sanitizing their pools.  The retailers in Florida, Southern Alabama, etc have anywhere from 300 to 500 gallon tanks of bleach at their stores.  The customer brings in a yellow container to get refills.  

Many pool services use bleach as well.  In fact, the largest pool service in Houston uses bleach with Cyanuric Acid as their primary method of shocking and maintaining chlorine in the pool.  They are very successful in doing this while keeping their pools in great shape.

[Vinny]

This is probably the last that I'll say about any of the recent posts on water care as these "discussions" are really worthless IMO.

Honestly I have used bleach and dichlor and dichlor for me is 100% easier to use as I keep it by spa side and just dose as I need it.

Personally I have learned a lot from chem geek on a different forum and he always is "happy" to answer a question - thanks! One of the things I learned from him is that dichlor = bad as is being portrayed in this thread is not entirely accurate. Also, he was the one that I learned from that the hot tub itch bacteria has to be introduced into the water and it just doesn't grow.

Yes chlorine becomes ineffective as CYA goes up but luckily the bacteria we are trying to kill is fragile enough to be killed even after 3 months use of dichlor which would be over 300 PPM. He advised me that keeping about 20 to 30 PPM CYA is the best place to keep it to keep the corrosive effects of chlorine at bay. The way to do that is use dichlor in the beginning and another form of chlorine after that - the bleach people prefer bleach.

Now, we come to the Dichlor = bad fallacy. I was lucky enough to be on Doc's forum when Vermonter posted a lot. Vermonter told us he is a Microbiologist and owned his own testing lab; he also tested his own water. If you believe what he was saying and I do, his water was safe from pathogens even at 3 months out using dichlor to dose and shock - that would give the tub a high reading of CYA. He did use ozone and nature 2 as well but attributed the water cleanliness to the dichlor. I doubt anyone else has tested and put the results down the way he did. Just based on this I believe that it is 100% possible to use dichlor and not have a problem.

I do believe that Chem geek and Vermonter have had a conversation at one point but I don't know if that's true.

But, it was also said that people may have issues. Chas has been doing this for a long time as has other spa professionals. Other than the people who only sell and don't get involved in any other aspects, I doubt that their experience is bogus. Yes, people have issues but how many times has a person come onto a forum and think they can use a product 1x or whatever without any idea of it being wrong or why. People are sold ozone without the use of sanitizer and then wonder why they have a cloudy tub ... maybe they were sold a bill of goods.

I agree also that you need to take info with a grain of salt on the internet. People have "accurate" information and it might indeed be accurate or not. We are all faceless people and quite honestly the theoretical vs practical knowledge may be different. I give my information based on my experience, I've been here a while as others have and I "trust" some people on what they say. If someone wants to use my info great, if they don't trust it - no skin off my nose.Coming onto a forum and being the "authority" without having a background on the forum is a little overzealous IMO. Personally I believe the info has been given out here will have a safe tub as well. Unless something is proven to be ineffective then it's not entirely wrong.

[Nitro]

Vinny,

The fact is, the Dichlor/Bleach method is cheaper and safer than using only Dichlor. Nobody can, or does dispute this. Also, there is a big difference between using only Dichlor, and using it with Nature2 and an Ozonator. This post is referring to using only Dichlor, without N2, an Ozonator or MPS. As far as which is easier, that's up to the individual to decide. Personally, I keep a plastic water bottle filled with bleach next to the tub, and squirt it in as needed. What could be easier than that?

I'm not saying using only Dichlor WILL cause problems. I'm saying it CAN (and HAS) cause problems. I didn't write this post to start a dabate (although I knew it would). I wrote it to inform people about the risks of using only Dichlor, and to give them an alternative. Like I mentioned before, I am not selling anything. And as you say, if someone doesn't take my advice, it's no skin off my nose. However, I will defend information that I know to be correct. And frankly, I find the fact that the industry, and some so called "experts" that I have personally came into contact with are ignoring this information, very troubling. Although not surprising.

[Gomboman]

I didn't have time to read all the posts here so pardon me if this was already covered. If CYA is a huge concern why not use Lithium Hypochlorite? I believe there is no stabilizer used in Lithium. Why doesn't a chemical manufacturer produce standard dichlor without a stabilizer for spa use?

I've used Vermonter's dicholor method for over 4 years now and have had no problems...................

[Nitro]

I didn't have time to read all the posts here so pardon me if this was already covered. If CYA is a huge concern why not use Lithium Hypochlorite?

The main reason is the price. It's about 17 times more expensive to use than Bleach.

Why doesn't a chemical manufacturer produce standard dichlor without a stabilizer for spa use?

They don't need to, becuase there's already a product called Bleach. However, you do need SOME CYA in the tub, or the Chlorine will be TOO strong. So using only Dichlor is much better than using only Bleach.

However, the real question is, why doesn't a chemical manufacturer produce a Starter Pack containing just the right amount of CYA to produce 20-30 ppm? They could also throw in some Borates as a bonus. On a fresh fill spa users could just throw the pack in the tub, and go right to using bleach. No need to measure CYA or calculate how much Dichlor you're using. Now THAT would be simple.

I've used Vermonter's dicholor method for over 4 years now and have had no problems...................

Glad to hear it, and I hope you never do.