I'm getting back into the hot tub routine after not having one for a while. Our new tub came with a chlorine dispenser and I just let it go since the water looked and smelled clean but when I got the Taylor kit it showed only 1ppm for free chlorine and a 14 or so for combined so time for a shock. I bought some bleach called Cloralen at the supermarket for only $2 and I called the company to find out the concentration which they first said was 2-6% and then they said it was 6%. Using the Pool math app I put in the shock amount but it barely changed the FC level. I put in twice as much and it barely moved again. Nowhere near the 12ppm I'm going for. Looking up the MSDS for the bleach it says 4-6% and it also has caustic soda 2%. Is this causing a problem? I had some Clorox and put in the recommended 5oz. and still only got to 5ppm. Another cup got me to 14ppm. The Clorox says 6.05% but when I looked at the MSDS it says 5-10% and the exact amount is a trade secret. Unbelievable to me that you can't get accurate amounts. No caustic soda listed for Clorox. Should I just get pool chlorine so I at least know what I'm getting?
Varieties of bleach
- Thread starter canman47
- Start date
- May 23, 2015
- 25,760
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
All bleach, no matter the brand, has caustic soda (lye or sodium hydroxide) in it. It is required to set the pH of the bleach above 12 so that the hypochlorite is stable. The caustic soda is not the issue.
- May 23, 2015
- 25,760
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Chloralen bleach is manufactured and used a lot on Mexico. It’s cheap bleach and probably closer to 3% than 6%.
Thanks, The Cloralen bleach was also dated a year and a half ago so probably lost even more . I'm still wondering about extremely high CC even though I've been shocking all day. With CYA at 30 I've kept FC above 12 for 4 hours now and still getting very high CC. I stopped at 50 drops because something seems really wrong. Water is sparkling clear. I'm not aware of putting any non chlorine shock in but maybe it's in the enhanced shock that came with the tub? The only listed ingredient is dichlor.
- May 23, 2015
- 25,760
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
It's a Frog @ease chlorinator with 2 cartridges, one for chlorine and one for silver. The chlorine one has 2 types of dichlor which are not the usual one. I also used the Enhanced Shock at first to get CYA up to 30. It lists Dichlor at 58% and then unlisted other ingredients. I used quite a bit at first. I was wondering about it since it says it's not a sanitizer. Since when is Dichlor not a sanitizer? Maybe I gave it a big dose of MPS?
- May 23, 2015
- 25,760
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
- May 23, 2015
- 25,760
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Ok, so the Frog @Ease system (by King Technologies) uses a mixture of chlorinated hydantoins - 81% 1,3-dichloro-5,5-dimethylhydantoin and 16% 1,3-Dichloro-ethyl-5,5-methylhydantoin. These substances are very slow chlorine sanitizers and, because they release chlorine so slowly, they cannot be registered by the EPA as recreational water sanitizers (their CT kill times are too slow to stop person-to-person disease transmission). However, they can be used in conjunction with an approved EPA sanitizer such as dichlor. So they get around the restrictions by stating in their instructions that the user must maintain an FC residual of greater than 1ppm and they must shock the tub weekly.
With a standard FAS-DPD chlorine test, the chlorinated hydantoin's are going to show up as CC's on the test because they will not turn the DPD dye pink very fast, only the free chlorine in the water will do that. Then, when you add the R-0003 reagent, the chlorinated hydantoin's react quickly with the iodine to then cause the DPD to turn pink. So even though you are registering high CC's, they are not CC's in the traditional sense.
So, in your case, if you use the @Ease system, you can only measure TC (total chlorine) in your tub. So what you do is add the DPD indicator powder, then add 5 drops of R-0003, then titrate with the R-0871. What you measure is the total chlorine which is the sum of the free chlorine and the reserve chlorine. You can certainly measure them independently as you have been doing, but the second number you get is going to be a mixture of reserve chlorine (chlorine bound to DMH/EMH) and whatever bather waste has been converted into true CCs. Unfortunately, there's no way to separate those numbers.
The Frog @Ease system also adds minerals to your spa (silver). There's nothing wrong with that but you may notice staining over time if they were to get too high.
If your TC is measuring above 5-6ppm, then you need to turn down your @ease chlorinator (does it have an adjustment?).
Did you purge this hot tub with Ahh-some before using it?
With a standard FAS-DPD chlorine test, the chlorinated hydantoin's are going to show up as CC's on the test because they will not turn the DPD dye pink very fast, only the free chlorine in the water will do that. Then, when you add the R-0003 reagent, the chlorinated hydantoin's react quickly with the iodine to then cause the DPD to turn pink. So even though you are registering high CC's, they are not CC's in the traditional sense.
So, in your case, if you use the @Ease system, you can only measure TC (total chlorine) in your tub. So what you do is add the DPD indicator powder, then add 5 drops of R-0003, then titrate with the R-0871. What you measure is the total chlorine which is the sum of the free chlorine and the reserve chlorine. You can certainly measure them independently as you have been doing, but the second number you get is going to be a mixture of reserve chlorine (chlorine bound to DMH/EMH) and whatever bather waste has been converted into true CCs. Unfortunately, there's no way to separate those numbers.
The Frog @Ease system also adds minerals to your spa (silver). There's nothing wrong with that but you may notice staining over time if they were to get too high.
If your TC is measuring above 5-6ppm, then you need to turn down your @ease chlorinator (does it have an adjustment?).
Did you purge this hot tub with Ahh-some before using it?
- May 23, 2015
- 25,760
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
And, by the way, adding dichlor shock is going to add CYA to your water. CYA is a chlorine buffer and it's going to take whatever free chlorine is in the water and bind to it. This is going to lower your active chlorine levels (hypochlorous acid) by quite a bit and could put you in the danger zone of where bacteria and algae can grow. So if you do need to shock the tub, it's best to just use straight liquid chlorine (aka, bleach), otherwise you'll really mess up the chemistry with the additional CYA.
Thanks for your very detailed explanation. That explains my high CC reading. I will not use the Frog system going forward because I want to know just how much FC and CC is present. The Frog dispenser never seemed to get FC above 1.5 anyway which I think is too low for a hot tub. I am aware of the CYA/chlorine relationship so I only used enough dichlor shock to get CYA to 30. No, I didn't purge the tub but I did fill it, run it, drain it and refill since it had a plastic smell to it.
- May 23, 2015
- 25,760
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Yes, the DCDMH and DCEMH release chlorine very slowly and their equilibrium reactions probably limits the amount of HOCl released so that it never really gets above 1-1.5ppm on an FC test. But you want to know something funny - DCDMH and DCEMH are used in another sanitation product - toilet bowl tank disinfectants!! That's right, those pucks that people hang in their toilet bowl tanks to create "clean" flush water are made of DCDMH and DCEMH (some even contain bromine in the form of BCDMH)...the same chemicals in are in those cartridges.
I don't necessarily have a problem with the Frog @ease system as long as the hot tub owner knows what they're getting into and how to handle it. If one wanted to use the Frog system, then you would have to use standard bleach to raise the FC a bit after soaking and probably use non-chlorine shock (MPS) every week just to be safe. So the trade-off is that the system might be a little less intense on the testing and dosing side (set it and forget it), but at the expense of using and buying more expensive chemicals. I bet those mineral and sanitizer cartridges are pretty pricey.
I would recommend you purge the tub with Ahh-some using the current water you have in it and then refill with fresh. Biofilms can be found in brand new tubs as well as old ones because they have to pressure test the tub at the factory which leaves behind a lot of stagnant water and humidity in the plumbing. Not to mention, a lot of the fittings are pipe-nipple type fittings with clamps and the manufacturers almost always use lubricants on the flexible tubing to get them to slide on easily. Many people have purged brand new tubs only to see lots of yellow/brown gunk come out of the jets and wondered why they were having such a hard time maintaining FC levels.
Good luck to you and happy tubbing.