Bubble Bath

[MPurcell]

Our new hot tub was originally filled on 2/8, so the water isn't that old yet. I've kept the water balanced and properly sanitized from the beginning, and my wife and I use it every day, without suits. We've been very careful not to introduce soaps and other things. Last Friday, 3/17, we had two guests use the spa for about 20 minutes wearing their bathing suits. Since then, when we run the bubbles (this type of spa does not have jets but puts a lot of air through hundreds of holes around the circumference of the base to thoroughly stir the water) the surface of the water foams up fairly significantly, and the foam will stay around for a bit, although it will eventually dissipate after about 10 to 15 minutes. I'm not ready to change the water for a while yet, so I'm wondering if taking the bromine up to shock level, say around 25 ppm would do anything to clear the soap out, or if not that, if I can use a flocculent without messing up the water chemistry. By the way, based on reading here, I thought that a Calcium Hardness of 150 is enough to prevent foaming.

Current water chemistry
BR 5
pH 7.5
TA 100
CH 250
Borates 50 ppm

thanks, Michael

 

[Arobbert]

Your guests probably had some detergent residue in their swimsuits and or soap/shampoo residue on them. This happened to me recently and is not unusual. It will eventually dissipate. You can use defoamer if the foam is bothering you. It doesn't take much detergent to cause foam.

 

[ant 83]

use a pool net, and scoop the bubbles out.

you can remove the foam this way.

 

[MPurcell]

Since I didn't get a direct answer to my two main questions in the OP, I used the search feature to do some research. I probably should have done that before I posted, but anyway what I found suggested that in pool foaming issues, taking the chlorine up to shock level will oxidize the foaming agents and eliminate the foaming without needing to change the water. So, I tried doing that over the weekend in my little hot tub. We skipped using it for one night, and on Friday night I took the bromine up to ~23. The following morning after 11 hours it was down to ~10. I let it sit till afternoon as I had other stuff to do, then at 2:00 pm I took the bromine up to ~25. That evening after about 9 hours it was down to ~13. So I pushed it up to ~28 and in 9 hours overnight it was down to ~18. By Sunday evening the bromine level had come down to ~10 so we could use the tub. The water was noticeably more clear, and the foaming issue was reduced but not completely eliminated. In my tub, there are two filters and they are in the water rather than external. When I changed the filters on Sunday afternoon, there was so much loose stuff that I couldn't get them out of the tub without making a cloud in the water, but that filtered off in a few hours.

I still have two specific questions.

Did I not hold the shock level of sanitizer long enough to do the job completely?

Can I use a flocculant without messing up the water chemistry?

 

[pooldv]

I don't know a lot about using floc and I don't plan to ever use it in my pool and tub. It might help because it is designed to coagulate solids into larger chunks so they will sink and you can vacuum them out.

Yes, further time with elevated CL/BR levels is needed to clear everything up. Not necessarily shock level if that hampers your tub time. Elevated sanitizer levels will always fix any organic problem in a tub or pool.

I would also consider doing a flush with Ahh-some and refill to just move past the issue.

 

[MPurcell]

Thanks for the input, @pooldv. I'm really reluctant to use floc, but at least it would go out with the next water change. But I don't think I'll go that route. I think I will try to keep the bromine level up to around 10 continuously and see if the foaming continues to diminish. We can live with it as it is now anyway for a while before we change the water. But I'm definitely going to put some Ahh-some on order. We also have a Jacuzzi style bathtub that is over 20 years old that has never had the plumbing cleaned out.

One other thing, it seems the recommendation for calcium hardness for a tub is in the range of approximately 150 ppm to prevent the type of foaming issue I have been having. Our fill water, which is from a ground water (bored) well, is very soft, less than 25 ppm CH. Yet, on my first fill I bumped the CH up to about 225 ppm and it is now around 250 ppm. As I mentioned in the OP, we have been very careful not to introduce much of anything in the way of products containing foaming agents into the water, so I am a little puzzled as to why I have this issue. Any thoughts on the matter would be helpful.

 

[alan55]

If the water is still clean I'd just use a net to scoop the foam...

 

[pooldv]

I agree with poster above that there was likely detergent in their swimsuits. CH at 125 will usually solve water foaming issues not related to detergent.

 

[MPurcell]

Thanks, @pooldv, that's an important distinction I was not making. I have kept the Bromine level up for the past week as you suggested earlier, not letting it drop below about 8 to 10 ppm.

The sudsing is manageable now. At this point, if I run the air blower into the tub for 5 - 10 minutes, it will build a mound of bubbles several inches thick, enough to completely cover up the floater. However, when the air is turned off, the bubbles dissipate rather quickly, and would be mostly gone within 5 minutes. I can swish them around with my hand to make them dissipate immediately, so they are not like soap suds. The water did not do this before the incident related above. It doesn't interfere with us using the tub, and if we run the air blower while we are in the tub, our presence keeps the bubbles down to a minimum.

But of course, being of a curious turn of mind, I want to know why!

 

[pooldv]

That sounds like the type of organic foaming that is usually fixed with 125-150 ppm of CH. Maybe some lotion or something? I don't know, but whatever it is you should hose off those people before you let them back into your tub. :-D

 

[MPurcell]

And it's down to this point after shocking for two days at 22 - 28 ppm bromine (equivalent to 10 - 12 ppm chlorine) and then holding the bromine up to at least 8 -10 ppm for a week since. And the CH is still 225 ppm. The bromine demand was fairly high during the shock days, but seems to have become quite a bit less as of the past day or two. I was under the impression that organic foaming is caused by substances that can be oxidized and filtered out.

 

[pooldv]

Yeah, I might not be using the right terminology. Pretty much anything can be oxidized but some things are more "sudsy" than others, like soap, detergent, etc.