13 replies to this topic

[more_air]

Hi, I've had an artesian spa for about 6 years. When I turn the bubbles on, it makes us cough. My PH and Bromine levels are correct. I change the water every 3 mos. Usually in the 2nd month the coughing starts. Any comments / help appreciated. Thanks in advance

[TinyBubbles]

Have you been coughing for the whole 6 years? You said "us", everyone that uses the tub coughs?

[more_air]

yes, coughing for 6 years...... and yes.... we all cough. talked with my dealer and he said to take the bromine floater out and use crystals once / wk.

giving it a shot

[biggz]

yes, coughing for 6 years...... and yes.... we all cough. talked with my dealer and he said to take the bromine floater out and use crystals once / wk.

giving it a shot

'more_air', I’m not a doctor, but what you’re describing is similar to Hot tub lung. I don't want to alarm you. It is treatable. I provided some links that we all should read. See link:
http://www.mayoclini...ub-lung/AN00660
http://www.webmd.com...-may-hurt-lungs

I also posted a link that dispels this finding.
http://findarticles....42/ai_104211201
This article is written by someone from the pool/spa industry so keep that in consideration.

This report from the Mayo Clinic has persuaded me to change my water when 2 months arrive and continue to do this thereafter. The spa companies suggest 3 months and the Mayo Clinic says 1 month so 2 I feel is a good compromise.

[chem geek]

The links talk about changing the water more frequently, but they don't explain why. I believe the primary reason is that most hot tub users sanitize with Dichlor and if you use that as your sole source of sanitation, then the Cyanuric Acid (CYA) concentration will build up and that makes the chlorine less effective (or requires a higher Free Chlorine level to compensate for this effect). So it isn't that the water gets old or anything like that, but rather that it builds up too much CYA. If one uses Dichlor initially for a week or two and then switches to unscented bleach, then the CYA will not build up and sanitation should be at more consistent levels.

It is also true that the additional buildup of organics in the water could also potentially interfere with chlorine's effectiveness (after all, CYA is an organic compound, though somewhat unique in the way it acts as a chlorine buffer) so changing the water after 3 months still makes sense. It's just that CYA is a known culprit in terms of sanitation reduction so I suggest not intentionally increasing its concentration through continued use of Dichlor.

The statement in the Mayo Clinic article that "added chlorine loses most of its disinfectant properties at temperatures above 84 F (29 C)" is simply not true. CT disinfection tables show that chlorine is actually more effective (has lower CT values) at higher temperatures. What this article may be referring to is that the rate of loss of chlorine from outgassing and breakdown from general reactions including oxidizing organics or ammonia happens faster at higher temperatures so it gets used up more rapidly. However, that can be compensated by using more chlorine or adding it more frequently or using a non-chlorine shock (MPS) to help reduce chlorine demand.

I can't prove that Dichlor is the culprit behind some of the hot tub lung cases. It's just a hunch based on some known chemistry, but as most industry professionals will tell you, real-life pools and spas have complicated chemistry not always matching what is found in the lab. Of course, I would just prefer that one tries a little harder to understand this more complex chemistry, but pools and spas don't get the same sort of focus as, say, atmospheric chemistry (ozone layer, greenhouse gas models, etc.).

Richard

[tony]

The statement in the Mayo Clinic article that "added chlorine loses most of its disinfectant properties at temperatures above 84 F (29 C)" is simply not true. CT disinfection tables show that chlorine is actually more effective (has lower CT values) at higher temperatures.

Richard, you are correct...chlorine is more effective at higher temps until you reach somewhere near 140 degress. Not sure where the 84 F number comes from but every once in a while this comes up.

[biggz]

The links talk about changing the water more frequently, but they don't explain why. I believe the primary reason is that most hot tub users sanitize with Dichlor and if you use that as your sole source of sanitation, then the Cyanuric Acid (CYA) concentration will build up and that makes the chlorine less effective (or requires a higher Free Chlorine level to compensate for this effect). So it isn't that the water gets old or anything like that, but rather that it builds up too much CYA. If one uses Dichlor initially for a week or two and then switches to unscented bleach, then the CYA will not build up and sanitation should be at more consistent levels.

Of course, I would just prefer that one tries a little harder to understand this more complex chemistry, but pools and spas don't get the same sort of focus as, say, atmospheric chemistry (ozone layer, greenhouse gas models, etc.).

Richard

Richard, I use 1 oz liquid chlorine after tub use and shock with dichlor every Sunday. Would I get better sanitation performance switching to common bleach? I really don't want to buy another chemical (MPS), so is there an alternate way to shock without adding (CYA) using chlorine. I should still have (MPS) from my start up kit. I guess I'll try some and see how it goes.

[chem geek]

First of all, 1 fluid ounce of 6% bleach in 350 gallons only raises the Free Chlorine (FC) level by 1.4 ppm which isn't nearly enough. You should add 3 fluid ounces to get to 4 ppm FC unless that builds up over time (depends on frequency of tub use). Even if you add chlorine so that you end up with a small residual the next time you get in, you want to make sure it doesn't get close to zero. Generally, 3-4 ppm FC gets used up in one day, depending on tub use and size. Also, 4 ppm FC with 20 ppm CYA is a conservative amount to ensure kill of hot tub itch bacteria.

You can shock with liquid chlorine (bleach) instead of Dichlor. The only difference between the two would be that the Dichlor shocking adds to CYA in addition to chlorine. You would get more consistent sanitation if you did that -- start with Dichlor for a week or two after a tub refill and then switch to liquid chlorine (bleach) for both dosing and shocking. To add 10 ppm FC, it would take about 7.5 fluid ounces in 350 gallons. One problem with shocking with chlorine is that it the FC is higher the next day. So you really don't need to shock unless you have to (more on that later).

You don't have to use a non-chlorine shock, MPS. It does help break down organics better than chlorine and it does help reduce chlorine consumption because of that. It also helps prevent the formation of chloramines. However, it has the downside of making some people break out if they are sensitive to it. If you find that the water gets dull or has an oil film or scum lines, you can use other products to deal with such issues including enzymes and scum balls (I didn't find them as effective as MPS for my pool, but every person's situation is different).

Be sure to keep the cover off for up to an hour after shocking, though 15 minutes would really help. During shocking, there is more formation of chlorine byproducts that outgas and aren't good for the cover.

Finally, if you don't measure significant Combined Chlorine (say, > 0.5 ppm), then you probably do not need to shock. This is most especially true in an outdoor pool exposed to sunlight where shocking is rarely needed -- if you do a regular (daily or after each use) dose to 4 ppm FC then you certainly won't need to shock for sanitation. A hot tub or spa that gets used a lot, however, builds up organics much faster and is not exposed to the UV rays of sunlight so usually needs to be shocked at least occasionally.

Richard

[biggz]

First of all, 1 fluid ounce of 6% bleach in 350 gallons only raises the Free Chlorine (FC) level by 1.4 ppm which isn't nearly enough. You should add 3 fluid ounces to get to 4 ppm FC unless that builds up over time (depends on frequency of tub use). Even if you add chlorine so that you end up with a small residual the next time you get in, you want to make sure it doesn't get close to zero. Generally, 3-4 ppm FC gets used up in one day, depending on tub use and size. Also, 4 ppm FC with 20 ppm CYA is a conservative amount to ensure kill of hot tub itch bacteria.

You can shock with liquid chlorine (bleach) instead of Dichlor. The only difference between the two would be that the Dichlor shocking adds to CYA in addition to chlorine. You would get more consistent sanitation if you did that -- start with Dichlor for a week or two after a tub refill and then switch to liquid chlorine (bleach) for both dosing and shocking. To add 10 ppm FC, it would take about 7.5 fluid ounces in 350 gallons. One problem with shocking with chlorine is that it the FC is higher the next day. So you really don't need to shock unless you have to (more on that later).

You don't have to use a non-chlorine shock, MPS. It does help break down organics better than chlorine and it does help reduce chlorine consumption because of that. It also helps prevent the formation of chloramines. However, it has the downside of making some people break out if they are sensitive to it. If you find that the water gets dull or has an oil film or scum lines, you can use other products to deal with such issues including enzymes and scum balls (I didn't find them as effective as MPS for my pool, but every person's situation is different).

Be sure to keep the cover off for up to an hour after shocking, though 15 minutes would really help. During shocking, there is more formation of chlorine byproducts that outgas and aren't good for the cover.

Finally, if you don't measure significant Combined Chlorine (say, > 0.5 ppm), then you probably do not need to shock. This is most especially true in an outdoor pool exposed to sunlight where shocking is rarely needed -- if you do a regular (daily or after each use) dose to 4 ppm FC then you certainly won't need to shock for sanitation. A hot tub or spa that gets used a lot, however, builds up organics much faster and is not exposed to the UV rays of sunlight so usually needs to be shocked at least occasionally.

Richard

Richard, I was under the assumption that liquid chlorine had more chlorine than Bleach. I'm adding Liquid Chlorine from the yellow refill that the pool supply house sells.

[chem geek]

No, if the "liquid chlorine" is normal pool store chlorinating liquid sold in strengths typically at 12.5% or 10%, then this is IDENTICAL to unscented household bleach except for its strength and the fact that bleach is typically sold in 3/4 gallon (96 ounce) containers while the chlorinating liquid is typically sold in 1 gallon jugs. There is nothing extra in the chlorinating liquid sold at pool stores or in some hardware stores (Home Depot).

[tony]

Richard, I was under the assumption that liquid chlorine had more chlorine than Bleach. I'm adding Liquid Chlorine from the yellow refill that the pool supply house sells.

You will use half the volume if using 10-12 percent liquid chlorine vs 5-6 percent liquid chlorine.

[biggz]

Richard, I was under the assumption that liquid chlorine had more chlorine than Bleach. I'm adding Liquid Chlorine from the yellow refill that the pool supply house sells.

You will use half the volume if using 10-12 percent liquid chlorine vs 5-6 percent liquid chlorine.

Tony, you and Richard are going to think I'm thick. So I'm using 1 oz liquid chlorine 10-13% in 300 gallons. Should I increase the dosage to 2 ounces and in using this will I build up (CYA) like if I was using Dichlor? Also not to hijack 'more_air's' thread any longer how will all of this help him. He's a bromine user.

[tony]

Tony, you and Richard are going to think I'm thick. So I'm using 1 oz liquid chlorine 10-13% in 300 gallons. Should I increase the dosage to 2 ounces and in using this will I build up (CYA) like if I was using Dichlor? Also not to hijack 'more_air's' thread any longer how will all of this help him. He's a bromine user.

biggz, there are no bad questions.

1 oz of the pool liquid chlorine (sometimes called pool shock) should bring your 300 gals to 2.5 - 3 ppm free chlorine which is pretty much where I bring my spa to after soaking. If you increase the dosage, you will not build up CYA as in using dichlor. Liquid chlorine is just double strength bleach and contains zero CYA. Your best bet is to dose and wait about 20 - 30 minutes and test for free chlorine. You will soon get a feel for your spas typical chlorine demand. This changes with number of soakers, etc. but you will get a very good idea of what your spa takes and can back off testing after a while.

[chem geek]

biggz,

You aren't thick -- I'm the one that calculated the dosage amount assuming 6% bleach while you are using stronger chlorinating liquid. Tony is right.

Richard