Do indoor pools require more chlorine?

Factual Questions
1

I checked out a gym today, and I haven’t actually swam it in yet, but the pool room reeked of chlorine. I remember another indoor pool I swam in was loaded with the stuff - much more than any outdoor pool I’d ever been in - so much that it intensely burned to open your eyes underwater.

I only have experience with 2 indoor, and a lot of outdoor pools - so this may not be standard, but if it is, why? (By the way, the desert scorching city of las vegas doesn’t actually seem to have outdoor pools aside from the ones at resorts. Annoying)

In a related question, are there health hazards to swimming in heavily chlorinated water? Does it do anything to your skin?

2

I think the heavier chlorine smell is due to the fact that the pool is indoors, Less air circulation. Outdoor pools have more opportunity for that Chlorine to waft away. Now, Public Pools probably use more chlorine than private pools. I have noticed the chlorine smell more at outdoor public pools. But then again, they tend to be Bigger than outdoor private pools, so you’d smell the chlorine more, because there’s more water there. I can’t think of a reason an indoor pool would need more chlorine than an outdoor pool of the same size and usage.

3

That makes sense, and I thought of that - it’s possible that that pool isn’t especially chlorinated. Before, though, in the other indoor pool I have experience with, the actual chlorine level was extremely high - you could feel it on your eyes, it wasn’t just a smell thing.

You may be right, though… I’ll find out later. I was just curious that if this was a standard thing, why it was.

4

Outdoor pools need far more chlorine; apart from it “wafting away” it’s also broken down by sunshine. What you are smelling is not the chlorine in the pool but that in the air, which is hugely concentrated in an indoor setting.

5

That doesn’t explain why the previous indoor pool I’ve swam in had water that was extremely chlorinated - you could tell by the taste and the way it burned the eyes. Of course, that one in particular may have just been run by people who wanted a really high chlorine level. I’ll have to wait till I swim there to find out.

6

Askance already gave part of the answer - outdoor pools need more chlorine when the sun is shining.

Secondly, it’s necessary to differentiate between the different forms of chlorine - the “free” chlorine that is added in the basement; the “bonded” chlorine after free chlorine bonds with the organic particles in the pool, and “chlorine mist” which hovers a bit above the water surface and is breathed in. (They’re all different chemically, but I can’t remember the correct chemical names right now, I’d have to ask).
Only one of the two compounds in the water actually causes the burning sensation - I think it’s the bonded chlorine, but I’m not sure without checking.
The chlorine mist is long-term carcinogen, so it’s not healthy to breathe in, but how much is there depends on the construction of the pool.

Generally speaking, the less chlorine in the pool, the better not only for your eyes, but also for your lungs; the more chlorine in the pool, the better for hygiene. Over here (Germany), public pools have very strict standards for both levels (amound of bonded chlorine indicates the amount of “dirt” in the water, but shall not exceed an absolute amount for health reasons), so the pool overseers (don’t know the correct English term for “Schwimmmeister”) have to regularly check the levels, and either add chlorine, or add freshwater.
Also, due to increased worry about long-term carcinogenic effects from the chlorine mist, the allowed levels of this have been drastically lowered over the last decade, leading to different pool design (stainless steel with the freshwater coming from the bottom, instead of tiled concrete and freshwater from the side; the water surface is level with the floor instead of half a meter below) which lower the problems.

However, since things are generally far less regulated in the US, it may be that the pool owner can dump in as much or few chlorine as he wants to, and you either run the risk of bad hygiene, or burning eyes. If it’s a real discomfort/you’re worried, could you speak to the pool owner/overseer how the chlorine levels are adjusted, ask to see the regular readings etc.?

7

(By the way, the desert scorching city of las vegas doesn’t actually seem to have outdoor pools aside from the ones at resorts. Annoying)

I hope your joking, but if you’re not: Las Vegas is in a desert, so water is a scarce, precious resource, that should be used responsibly. An outdoor pool in a desert is just an expensive way of letting lots of precious water evaporate away for nothing, instead of drinking it and swimming indoors.

As for why some pools might have high chlorine levels: were they less frequented? Maybe the owner wanted to save water, so instead of regularly replacing stale and used water by adding freshwater, he just added a high amount of chlorine without checking every fortnight? (I guess the automated chlorine dosage systems are a bit expensive, and if the overseers/owners is too lazy to bother with manual readings… you end up with badly adjusted chlorine levels.

8

I considered this, and it’s probably the reason. Water doesn’t seem in horribly short supply here, though. The colorado river seems to provide plenty of it. I’ve never seen anything about any sort of water rationing, water is cheap (at least it’s free in apartments - I’d imagine that means it’s cheap), and sprinklers are used for decorative grass.

I figured in an area with 120 degree heat, a public pool system of some sort would seem like a reasonable way to provide recreation without anyone dying of heat stroke. It seems that if water can be spared for sprinklers for decorative grass, it could be spared for a few large public pools.

9

My wag would be that your eyes burn in the indoor pool since the air around the pool has more chlorine due to less ventilation. More chlorine hovering above the pool will mean less chlorine leaving the water so the chlorine level in the pool says more constant.

Outdoor pools, may have more added, but that extra quickly evaporated, well sort of undisolves, and blows away, so the air above the pool is less chlorinited, which make it eaisier for more chlorine to undisolve.

10

That’s also related to the “wafting away”.

Part of the Chlorine in the water is not in the form of Chlorine… it’s Cl- or ClO- or… but part of it is Chlorine, Cl2. Which is not very water-soluble and like most gases is less water-soluble at high temperatures.

Some of the Cl2 moves to the air. In the summer, an outdoor pool is more likely to have higher temperatures, so more Cl2 will be moving to the air. And what moves to the air will dissipate away: think of putting a teabag in a cup of hot water and not moving it, you can see the water get brown around it; we move it to speed the process but eventually the whole cup would get brown. The transfer of Cl2 to the air is a two-way process: molecules of Cl2 go in and out of the water - but they can’t go back in if they’ve moved away. As the Cl2 moves away, more Cl2 molecules leave the water… the Cl2 moves away… so, air currents are sort of “pulling” the Cl2 out of the outdoor pool.

The indoor pool, first it’s likely to have cooler air on top of it (again, in the summer) so less Cl2 will be leaving the pool in the same amount of time. That Cl2 will disperse in the enclosed air - but only in the enclosed air. I cheated with the teabag example: you see, the open pool is like a teabag dropped, not in a glass, but in the middle of the ocean. The closed pool is the one that’s in a glass, and a pretty small one. So the Cl2 that leaves the pool is not going anywhere - if the building was completely sealed, equilibrium would be reached and the water would never need to be rechlorinated. Of course, that would make for a pretty lousy swimming pool!

11

Water doesn’t seem in horribly short supply here, though. The colorado river seems to provide plenty of it. I’ve never seen anything about any sort of water rationing, water is cheap (at least it’s free in apartments - I’d imagine that means it’s cheap), and sprinklers are used for decorative grass.

I don’t want to start ranting, - and this is directed against you, because you just observed, you aren’t responsible for this - but the facts are that
-Las Vegas is in a desert, so water is scarce
-For me, it’s scandalous how it’s wasted on things like green grass that have no business being there
-The reason it’s wasted is not abundance of water, but because it’s cheap (as you already said), laziness and apathy of the consumers (they don’t know and don’t care about the consequences)
-The reason why the water is cheap enough to be squandered is related to unfair distribution of water rights (i.e. the rich and powerful elite in the US states through which the Colorado river flows have all the rights, the Mexicans downstream of the river get a thin trickle, but don’t have enough clout to change it)
-And because not enough people care about the consequences (ecologically and economically) of draining the Colorado river almost dry, this will continue, as bad as it is.

*I figured in an area with 120 degree heat, a public pool system of some sort would seem like a reasonable way to provide recreation without anyone dying of heat stroke. *

If by recreation you mean sports, it’s quite possible to do sports in 120 degrees (that is about 50 C, right?) without outdoor pools - use indoor pools, do sports early in the morning or late at night, not at noon when the sun glares down, etc.

Same for recreation - go in the shade, take it slow, etc.

In other words: adapt yourself to the enviroment, not the other way round. This is the ecologically friendly way - uses less resources. And not forcing your body to perform to an arbritary schedule, but instead listening to the rhythm, is also better. (Why do you think people living in hot climates have long siestas? Not because they are lazy! They start working when the sun is less intense, in the late afternoon, again.)

As for public system of recreation - that’s natural for me, that the community takes care of providing a basic infrastructure. But my impression was that this is uncommon in the US, because the majority of Americans doesn’t want the state “interfering” or being “nanny state” (even if it means things like infrastructure, where only the state is the reasonable supplier), and they don’t want to pay higher taxes for these things? At least, that seems to be the dominant opinion on the net and media.

It seems that if water can be spared for sprinklers for decorative grass, it could be spared for a few large public pools.

Or rather, water shouldn’t be wasted either for outdoor pools nor for green grass, because both are frivoulous.

12

When I was a young lad, our team swam in an overly chlorinated, indoor pool for one practice, and the entire team came down with respiratory problems. It was a severe overdose, though, and our coach was an idiot for making us continue to swim while wheezing with asthma and such. Nonetheless, a hazard, albeit unlikely.

In addition to the suggestions already mentioned, there’s a strong possibility that the people treating the pool chemicals are just doing it wrong. It’s more usual for them to under-treat the pool (chemicals are expensive), which gives you milky, cloudy water. This is especially likely if the pool has (young) lifeguards check the pool chemistry, instead of someone more experienced like the pool manager.

Chlorinated water is also very drying to your skin and hair, and of course leads to lovely “chlorine hair” if you’re fair-haired – straw-like and shiny. AFAIK there’s no greater risk of these if the chlorine concentration is a little higher than usual, though.

13

According to a friend who was responsible for the water treatment of both indoor and outdoor pool the chlorine demand was directly related to the number of occupants ANF the make up of those occupants as to age, sex, and whether mixed or single characteristic groups.

14

I guess it depends where in the US you are. Here in Massachussetts there is an extensive system of state run parks and swimming pools, many of them in Boston and adjacent urban areas:
http://www.mass.gov/dcr/recreate/swimming.htm

I know for a fact many of the (admittedly wealthy) towns I or my relatives and friends have lived in in Mass. or New York State have had municipal pools paid for out of local tax dollars.

15

Bolding mine

Disclaimer - I’m no expert. I’m just trying to logic through this

No offense intended to Constanze but I don’t think decision makers in the Las Vegas area are concerned about the moral responsibilities of conserving water.

More than likely you’ve provided a big clue as to the lack of pools. With temps as high as that area of the dessert provides I suspect that cool water turns into bath temperature water rather quickly. I too saw the outdoor pools of the resorts at Las Vegas and assumed that they had to continually replenish the water to make it enjoyable for their guests. They can afford to throw away money on high water bills because their guests are throwing away so much money in their casinos.
As to the Op’s Chlorine questions. Outdoors the sun and wind remove chlorine quickly from the pool and immediate vicinity. Indoors the chlorine dissolves out of the water and into the air where it stays untill air circulates out of the room. In the air the chlorine will continue to irritate your eyes and lungs so you are “bathing” your eyes in chlorine continuously indoors while limiting exposure to “underwater only” when you are outdoors. Add that to overchlorinating by the operators of the indoor pool you visited and you will very easily notice a difference between indoor and outdoor pools.

16

It’s hard to be sure at this late date, but I would bet that the source of the respiratory distress was not caused by too much chlorine, but by chloramines, paradoxically caused by too little chlorine.

In a pool environment, free chlorine oxidizes organic material in the water. If there is not enough free chlorine to complete the oxidation, it bonds to the organics to form chloramine, NH2Cl. This stuff is very irritating, down to about the 0.3 ppm level, worse than chlorine.

17

It’s not the chlorine that causes irritation with most folks, as noted above. It’s a dirty pool that causes the red eyes, as the chlorine has reacted with the, uh, organic compounds in the pool. A properly adjusted Ph, chlorine, filtered water, etc., is really nice, and not the least irritating.