Fizzing Water

[TreeFiter]

I have noticed for quite some time that some hot tubs will be crystal clear and balanced when I arrive, but once I turn the jets on they become cloudy. After turning off the jets the cloudyness bubbles off as a fizz, and eventually, usually within a few minutes the water returns to clear.

What causes this? Is it a problem, beyond cosmetics?

 

[chem geek]

It's cosmetic and is due to the dissolved gasses in the water when using aerating jets. Air bubbles in water can make it look cloudy or milky. This happens with water running from faucets as well, especially when they have aerators. When air bubbles in water are larger, you see them as distinct bubbles, but when they get small, then you don't seem them as separate bubbles and instead they refract/reflect the light making such light more diffuse rather than see-through. The same effect happens with white clouds in the sky except in that case we have fine water droplets in air instead of fine air bubbles in water. The difference in refractive index between the two causes the same sort of diffuse reflections/transmissions when there are a lot of these small bubble interfaces.

 

[y_not]

Are you sure there aren't any Alka-Seltzer tablets falling in there when you aren't looking?

WOW Chem Geek! Thanks a bunch for that awesome info.
You know my silly 2nd cousin and her BFF, they were almost 13 at the time. They'd jump in my aunt's pool and when they surfaced they'd yell, "TINY BUBBLES" over and over because of all the little bubbles on their skin from diving.
LOL DORKS! :lol:

So I'm to ascertain that no hot tub can be clear while running, or afterward. Correct?
Just the nature of the beast it sounds like.

 

[UnderWaterVanya]

My municipal water has this problem from time to time - enough so that there is an FAQ on the site. It's funny looking - essentially as the water pressure drops drastically all that pent up gas comes out of solution into tiny bubbles that make the water look milky. The key is that if the water sits for only a minute or so you'll see the tiny bubbles joining each other and then liberating themselves at the surface until the water is clear again.

 

[TreeFiter]

What causes it to happen though? I've had hot tubs where over time they seemed to become more and more cloudy, and once I changed the water, they were sparkling clear again. Is there something in the chemistry that makes it come on over time?

 

[y_not]

My municipal water has this problem from time to time - enough so that there is an FAQ on the site. It's funny looking - essentially as the water pressure drops drastically all that pent up gas comes out of solution into tiny bubbles that make the water look milky. The key is that if the water sits for only a minute or so you'll see the tiny bubbles joining each other and then liberating themselves at the surface until the water is clear again.

WOW MAAAANNNN!!!! You like have liberated water maaaan??
MEEEE TOOO MAAAANN!!! COOOOOLLLL

 

[chem geek]

What causes it to happen though? I've had hot tubs where over time they seemed to become more and more cloudy, and once I changed the water, they were sparkling clear again. Is there something in the chemistry that makes it come on over time?

Some substances such as soap-like substances in the water create direct foaming (soap bubbles) which can cloud the water but usually result in foam at the surface. Other substances can reduce the surface tension of the water without causing foaming (e.g. boric acid) which would allow for faster dissolving of air into the water. So over time, the water chemistry may be changing. If your Calcium Hardness (CH) is low, you might try raising it to 120-150 ppm and see if that helps since the harder water will inhibit foaming from soak-like substances.

If you are using Dichlor-only, then the buildup of Cyanuric Acid (CYA) over time will lower the active chlorine (hypochlorous acid) level which will slow down its disinfection and oxidation rate. That can result in a faster buildup of organics that don't get oxidized as quickly and so the cloudiness can be from such chemicals that may not dissolve well in water until oxidized (i.e. until they become more polar). The Dichlor-then-bleach method prevents this problem from happening. What type of disinfection was being used in the hot tubs that had the cloudiness problem that got worse over time?

 

[TreeFiter]

A few of them were bromine tabs, but the last one was using oxy shock and granular chlorine. The last one was notably fizzy to where you could hear the bubbles coming out like when you pour a glass of soda. The others didn't have such pronounced fizz, and it would tend to hang in the water longer.

 

[chem geek]

That makes sense since granular chlorine was probably Dichlor so over time the CYA would build up and the chlorine wouldn't oxidize the bather waste as quickly so the water could cloud up more. For bromine tabs, one usually needs to shock with chlorine on occasion since bromine alone doesn't oxidize as much bather waste, or so it seems, to keep the water clear. However, these effects would tend to make the water cloudy even without the aeration from the jets. Perhaps the combination of cloudiness becomes more noticeable when the water is "dull" to start with and then aeration makes it look much more cloudy. Either that or some of the built-up chemicals that aren't getting oxidized as fast over time are directly contributing to bubble formation/retention.

 

[TreeFiter]

I typically use oxy shock in my bromine tubs. I haven't noticed the water to be dull before the jets are turned on. I guess its not all that critical. Its usually easily fixed by changing the water. It kind of serves as a good indicator for when to change the water.

 

[TreeFiter]

I decided to revive this thread, because I was speaking with one of my customers a few days ago, and he told me something that he was told by the company that sold him his hottub. I had noticed that the water was becoming dull, so I told him it was a good idea to change the water. He was going to change the water himself. So the following week I talked to him again. He told me that he hadn't changed the water, but somehow the water had become sparkling clear again. He told me that he had a service guy out to repair the speakers in the hot tub, and they told him to run the jets with the cover propped up slightly to let some air pass in and out.

I'm wondering if this is a legitimate way to clear up a cloudy tub, given the right situation, and how/why this works. I should also mention that the chemistry in the tub is always pretty good. The tub uses a Frog floater system, which consists of two cartridges, one bromine, the other a mineral pack. I adjust pH and TA weekly, and I add OxyShock once a week as well.

 

[chem geek]

Perhaps if the jets aren't normally used, then the stagnant water in them gets contaminated while running the jets with chlorinated water cleans them out. However, I'm not sure if such contamination would cause the water to get cloudy. It could cause increased chlorine demand.

The other effect of running the jets is aerating the water. If that were to consolidate suspended particles so that they got caught in the filter, then that could clear up the water. Some of this is described in this link, but I don't see how this applies since iron should get oxidized by chlorine so doesn't need oxygen to do that. It may be removing some partially dissolved gasses so to the extent that some of these made the water cloudy then that might work, but that still seems like a stretch to me.

 

[TIMMAH]

i just got this, i jumped in and i could hear it fizz like soda. i was getting a constant mist from it. we didn't have really much foam, maybe a 1/8 to 1/4 in of small fine foam. i used a pre filter on city water to fill it. my ch is in the low 200 so i added water from the water softer to the tub to top it off 2 or 3 times so far. i know a few drops of dish washing soap got into the bucket i used in the sink to get the soft water from. we have a dish soap bottle with a pump nozzle on it that was hagging over the bucket we had just added 12 gallons of soften water. but this didn't happen over night. i notice it went from clear water with the jets on to the white it is now over the last 7 weeks.

the wife puts lots of lotions on but always takes a shower before getting into the tub.

i'm thinking the lotions the wife put on don't really come off on the shower.
or the soften water is reacting with the hard water? becasue we had just added 12 gallons of soften water.

this is the first time i've seen this and we have had a tub since 2002. i use to mix my old tub with half soft water and half hard when filling it.

about 5 years ago i had a friend come over before with jean shorts on and the tub had 8 inches if suds after a few minutes with him in it lol. but it went away with a little defoamer.

anyways i added a little defoamer and water clarifier. if i get a change i'll post up. after my next water change i'm only going to use the hard water with the pre filter and i'll post up if i don't or do still get the problem. if i still do i would have to guess it's the wifes lotions.

 

[chiefpontiac]

I decided to revive this thread, because I was speaking with one of my customers a few days ago, and he told me something that he was told by the company that sold him his hottub. I had noticed that the water was becoming dull, so I told him it was a good idea to change the water. He was going to change the water himself. So the following week I talked to him again. He told me that he hadn't changed the water, but somehow the water had become sparkling clear again. He told me that he had a service guy out to repair the speakers in the hot tub, and they told him to run the jets with the cover propped up slightly to let some air pass in and out.

I'm wondering if this is a legitimate way to clear up a cloudy tub, given the right situation, and how/why this works. I should also mention that the chemistry in the tub is always pretty good. The tub uses a Frog floater system, which consists of two cartridges, one bromine, the other a mineral pack. I adjust pH and TA weekly, and I add OxyShock once a week as well.

I have the same problem in my Bromine spa. It happens over time and eventually the mist from the fizzing is so bad it starts to make the bathers gag. The only thing I've been able to do is change out the water, but I, too, would like to find a solution to the cause. I agree there must be a chemical imbalance or saturation going on. Did you ever solve this?