Hi Nitro And Chemgeek

[LauraG]

It has been a while since I've needed your help!! Things have been going quite smoothly with the hot tub, until last week. I had been following the 'plan' quite well and had no trouble at all. My husband has the rash that he had last winter, but I thought it was 'just him'. Last week (Wed) a couple of our friends were over, and the next day they both say that they were very ithcy and had rashes. I did not.

My readings were pretty good before we got in, I added Purox afterwards( the same routine that has worked all these months).

The only thing I can think of that I did NOT do was add MPS for a couple of weeks beforehand. I had been shocking with MPS weekly, but ran out , so just shocked with Purox. Do you think that the FC was too low by the end of the evening? The TA and the pH were fine just before we got in. I did not check while we were in, but we weren't in as long as usual. Perhaps 1.5 hours or so. I shocked with MPS on Thurs. and was in for quite a while on Sat. and no ill effects.... I feel kind of badly that my friends woke up itchy and scratchy! They called my husband and told him it was the Purox, and they can't come in the hot tub anymore.... I don't believe it was the Purox....but perhaps the 'lack' of it...?

[chem geek]

If you haven't been testing your Free Chlorine (FC) level to know that you've had enough for a residual before each soak, then I think you've answered your question. You probably got to a very low or zero chlorine level for too long a period of time so hot tub itch bacteria could then grow. Also, I'm not sure how you are switching between using bleach vs. using MPS. The MPS can supplement the bleach, but cannot ever replace it (since you don't have N2). So perhaps when you weren't using MPS, then you didn't use enough bleach and the chlorine got to a low level. This would make sense if your husband only got the rash recently after this switch to not using MPS occurred (when did your husband start getting his rash again?).

What were the readings before you got in the tub with your friends? How long has it been since the last water change? Do you do a high-level shocking after a water change?

You should do a decontamination procedure and then watch your chlorine levels more carefully. If I recall, your tub is rather small and you use it heavily so have a very high bather load and would need to replace the water sooner than most anyway, even using the Dichlor-then-bleach method.

If you look at the list of hot tub inicidents, most are due to low or no chlorine for a period of time, some are after 1-2 months of Dichlor-only use, and I think only one was with N2 but with low or no chlorine. The N2 is a good insurance policy if the chlorine gets too low. The problem with any "add every day" system is that you have to be really diligent and in your case it's extra difficult due to the very high bather load.

I forget -- are you using 50 ppm Borates? I think with your small spa and the large FC swings that it would be a good idea to prevent the pH from varying a lot.

Richard

[Nitro]

Hi Laura,

Sorry to hear about your troubles. I agree with Chem Geek here. It sounds like because you stopped using MPS, that put extra demand on the Chlorine. If you didn't increase Chlorine to make up for it, your FC would have dropped lower than usual. I would do as Chem Geek says, Decontaminate, and start over. Make sure you keep your FC at least 1 ppm at all times while soaking, even more with guests. MPS is also good to use with guests, because it takes some burdon off the Chlorine. Also, keep track of your Chlorine Demand. If you see CD rising from where it is on a fresh fill, it means you're not using enough Chlorine. Check out my links below for more info.

Here's a couple ideas I came up with. Keep a 16 oz plastic water bottle filled with Bleach next to the tub (easy access will soaking). During long soaks, just squirt an ounce or two in the tub once in a while. This will keep the FC more consistant, and will actually reduces the smell of the Chlorine. Also, if you plan on having a hot tub party, keep a plastic container with MPS next to the tub. Just sprinkle a teaspoon here and there, before and during the soak. If you do this you may not even need to shock (though it won't hurt). The key is to keep the Sanitizer/Oxidizer constant.

Keep us updated.

[LauraG]

If you haven't been testing your Free Chlorine (FC) level to know that you've had enough for a residual before each soak, then I think you've answered your question. You probably got to a very low or zero chlorine level for too long a period of time so hot tub itch bacteria could then grow. Also, I'm not sure how you are switching between using bleach vs. using MPS. The MPS can supplement the bleach, but cannot ever replace it (since you don't have N2). So perhaps when you weren't using MPS, then you didn't use enough bleach and the chlorine got to a low level. This would make sense if your husband only got the rash recently after this switch to not using MPS occurred (when did your husband start getting his rash again?).

What were the readings before you got in the tub with your friends? How long has it been since the last water change? Do you do a high-level shocking after a water change?

You should do a decontamination procedure and then watch your chlorine levels more carefully. If I recall, your tub is rather small and you use it heavily so have a very high bather load and would need to replace the water sooner than most anyway, even using the Dichlor-then-bleach method.

If you look at the list of hot tub inicidents, most are due to low or no chlorine for a period of time, some are after 1-2 months of Dichlor-only use, and I think only one was with N2 but with low or no chlorine. The N2 is a good insurance policy if the chlorine gets too low. The problem with any "add every day" system is that you have to be really diligent and in your case it's extra difficult due to the very high bather load.

I forget -- are you using 50 ppm Borates? I think with your small spa and the large FC swings that it would be a good idea to prevent the pH from varying a lot.

Richard

The FC is tested on a daily basis, and I have never missed adding Purox daily. I suspect that for some reason that night, there just wasn't enough left in as we soaked..... I always add in more right afterwards, as well.

The tub is 380 gallons.

I do have a question for you. We did a water change in March. We gave it a good cleaning, used swirl away, and was able to buy 10 Mule Team Borax. I am not sure if I have 50 ppm Borates!!! How do I measure that? I was not sure about that, so I put in 19 Tablespoons, then a week later put in another 10 tablespoons. I do not have a really high bather load any longer. I am using MPS to supplement only,and had not used it for a couple of weeks, but shocked with purox. I still used enough Purox, I was very diligent.

Right now I am lowering the TA, which is 120.

Today's reading are FC 3.0 The usual reading before I add more Purox for the day.

pH 7.6

CC 1.0

TA 120 (as I said, I am lowering this as I type)

CH 120

[chem geek]

Thanks for the info. At 380 gallons, I got mixed up with another tub user -- your load isn't as extreme. I'm glad you are regularly testing. And I'm really sorry this bad experience happened.

Well, not having chlorine up during a soak does mean that person-to-person transmission of pathogens is more likely so if your husband had hot tub itch, then that could explain how it spread. It does not, however, explain how he got it in the first place. Though one could certainly have sanitizer level up during a soak, and in commerical/public pools and spas that is what is done, the downside is that you will smell the chlorine and monochloramine from the bather load. That's the tradeoff. It doesn't matter if you used bleach, Dichlor or any other source of chlorine in terms of not having enough or any while you soak.

To get to 50 ppm Borates in 380 gallons, it takes 42 tablespoons of 20 Mule Team Borax and and 11 ounces of Muriatic Acid, but it's much easier/safer to use a pH balanced product such as Gentle Spa where I believe you would use around 32 tablespoons (2 cups) of product.

Do you recall what the hot tub situation was when your husband got his itch? Something isn't good enough in your tub situation for him to get hot tub itch in the first place so we need to figure that out to prevent it from happening again. Though maintaining FC even during a soak would likely work, it's also what most people don't want to do since they want to avoid smelling chlorine/monochloramine during the soak. As I mentioned in the earlier post, those with N2 systems seem to have a lower likelihood of problems probably due to the extra level of sanitation that's always there even when the chlorine level is low or zero (such as during a soak).

I think that this happening after you stopped using MPS, assuming that the bleach level was increased which it sounds like it was, may have been a coincidence. Did your husband start re-experiencing his itch after this change, or was that before?

Richard

[LauraG]

Thanks for the info. At 380 gallons, I got mixed up with another tub user -- your load isn't as extreme. I'm glad you are regularly testing. And I'm really sorry this bad experience happened.

Well, not having chlorine up during a soak does mean that person-to-person transmission of pathogens is more likely so if your husband had hot tub itch, then that could explain how it spread. It does not, however, explain how he got it in the first place. Though one could certainly have sanitizer level up during a soak, and in commerical/public pools and spas that is what is done, the downside is that you will smell the chlorine and monochloramine from the bather load. That's the tradeoff. It doesn't matter if you used bleach, Dichlor or any other source of chlorine in terms of not having enough or any while you soak.

To get to 50 ppm Borates in 380 gallons, it takes 42 tablespoons of 20 Mule Team Borax and and 11 ounces of Muriatic Acid, but it's much easier/safer to use a pH balanced product such as Gentle Spa where I believe you would use around 32 tablespoons (2 cups) of product.

Do you recall what the hot tub situation was when your husband got his itch? Something isn't good enough in your tub situation for him to get hot tub itch in the first place so we need to figure that out to prevent it from happening again. Though maintaining FC even during a soak would likely work, it's also what most people don't want to do since they want to avoid smelling chlorine/monochloramine during the soak. As I mentioned in the earlier post, those with N2 systems seem to have a lower likelihood of problems probably due to the extra level of sanitation that's always there even when the chlorine level is low or zero (such as during a soak).

I think that this happening after you stopped using MPS, assuming that the bleach level was increased which it sounds like it was, may have been a coincidence. Did your husband start re-experiencing his itch after this change, or was that before?

Richard

Thanks for your help.

Because I really don't think the hot tub is contaminated--I don't want to do a water change already. The test results have always been fine---I think I must have slipped up though last week, perhaps there wasn't as much in as I thought, for a short time. Right afterwards I added more Purox, and the next reading was still fine--so I never did get a 'bad' reading. I shocked it the next day, and used it several times over the weekend with no trouble. That is why I suspect that on the Wed. (before shocking with MPS, ) I had the problem. It was our two friends who woke up with a rash and they were itchy. I was fine.

My husband got the same rash he had last year. He has had the skin problem for a couple of months now atleast. The doctor told him it was excema, so I haven't been too worried about him (poor guy). It seems his problem has nothing to do with the tub. I am hoping that.

It would seem that I did not put in enough of the 20 Mule Team Borax. Also, what do I add to get Muriatic Acid in there? Crazy question, I know, but I want to be clear.

Next refill. I'll use the Gentle Spa substitute as I did last time.

Today's readings:

FC 3.5

pH 7.0

TA 70

I do the readings usually at the same time each day.

I have been aerateing to get the pH to rise, and it is now at 7.4 There seems to be a lot of foam though. This is another new development.

[chem geek]

20 Mule Team Borax will raise the pH considerably when you add it. Though I said Muriatic Acid, you could have used dry acid (sodium bisulfate aka pH Minus) when you used the Borax -- that's probably what you did.

As for the foaming, test your Calcium Hardness (CH) and if it's less than 120 ppm, add some calcium chloride (Calcium Hardness Increaser) to get to 120 ppm.

[chem geek]

Laura,

Based on this chart it sounds like your friends had more of a chemical reaction (sensitivity) than a bacterial infection (since it showed up < 24 hours). So I wonder what was in your tub that cause this. Some people are sensitive to MPS but you stopped using that a couple of weeks before your friends used the tub. I wonder if the Purox has something in it that some people are sensitive to. I assume it's unscented and just plain bleach which is chlorine, salt and water with a small amount of excess lye in it.

I also wonder if your issue with foaming has anything to do with something in your tub that is irritating to some people.

By the way, if you are soaking for hours typically, that is a high bather load.

Richard