Quote from: wattMaster on July 09, 2016, 10:26:12 AM

Why not have big water storage tanks to keep the water?

Double the cost of the pool building...

The pool itself is usually very huge water storage and the most expensive on it§s building is to make sure it holds that amount of water and does not leak in either direction. The fact it is accessible for swimming is just small portion of the building cost. So an extra storage means paying an extra pool, just without the possibility to use it in such way.


Of course, a small home refreshing pool cost few order of magnitude less than an Olympic sport swimming pool, but I don't think the relative contributions by different parts (tme main tub, water treatment equipment, roof, water content itself,...) to the total cost are not that much different...


I think the indirect lighting using the mirrors above the pool is not that bad idea - the electrical stuff (which is the part that tends to break without warning) is only on the sides, where you may access it anytime you want without messing up with the water, above the water are just the mirror panels, which need just some cleaning as a maintenance and that can be well sheduled/postponed till the time, when the pool water is going to be replaced anyway (usually once a year or so).
Otherwise with higher ceiling lights, you will need some scaffold system or so anyway, so then the water underneath is not relevant for the electrical work (it would be just another humid environment).

The bad part comes when someone wants to throw an object at the mirror to see what happens.

The mirrors for this use to be polished stainless steel with circular grooves in it (to not be that sharp bright light source, as well as to strengthen the material). So in the worst case he could just bend it a bit...
Such system is used e.g. on the top right are visible three such round mirrors (this is the only picture I've found where at least some were visible; otherwise these were all over the ceiling, illuminated from the columns by a similar reflector "batteries" as seen on top of the reversed cone).

Looks interesting, but the flood lights would be on the side of the pool, not in it.

I think too, easier will be to keep all the reflectors on the sides. That was what I meant...

And for the reflectors, you will need some really narrow beam types, so they can focus most of the light onto its corresponding mirror panel (each lamp has it's "own" mirror...)...

I choose that picture, because there was no other with the mirrors visible...
In that Kohoutovice pool, the column hosts mainly all the pumping machinery for the massage sprays and the "wild river" around it, so the electrical installation was there anyway, so they used that for the lighting installation too.

Thats not the only option

 - Uplight a flat White ceiling, that can be done with way more wide beam floodlights. Its reflection is a bit less efficient than the stainless, but it may come out as good on the overall, as there is no light hitting from the side and into behind the mirrors

 - Light into the skylights of the building or under removable skylights, so you can walk to them on the roof of the building

 - Light in the sides of the pool and leave it at that. Not uniform lighting but not uniform does not mean not good

Thats not the only option

 - Uplight a flat White ceiling, that can be done with way more wide beam floodlights. Its reflection is a bit less efficient than the stainless, but it may come out as good on the overall, as there is no light hitting from the side and into behind the mirrors

 - Light into the skylights of the building or under removable skylights, so you can walk to them on the roof of the building

 - Light in the sides of the pool and leave it at that. Not uniform lighting but not uniform does not mean not good

Didn't think of that.

Thats not the only option

 - Uplight a flat White ceiling, that can be done with way more wide beam floodlights. Its reflection is a bit less efficient than the stainless, but it may come out as good on the overall, as there is no light hitting from the side and into behind the mirrors

There is a question, how to maintain the ceiling reflective enough. But it could be made complementing the mirrors (so the spill light isn't that lost)

- Light into the skylights of the building or under removable skylights, so you can walk to them on the roof of the building

I think that would be even worse nightmare to maintain than just having them straight above the pool: Climbing over the roof,...

- Light in the sides of the pool and leave it at that. Not uniform lighting but not uniform does not mean not good

That could be a problem for the lifeguard service: They have to have very good view mainly to the underwater area and for that you need lighting practically straight from above. If something happens, the time for them to respond is running very fast...



But the direct lights directly above the pool do not have to be that big problem in some cases.
On many places (but those were really sport stadiums, with at least one tribune and so on) I've seen a service portal used when "parked" as an elevated observation deck - mainly used by trainers to have good overview about how their clients perform, so be able to give better addressed advices. But with some sport events it was used for referees, I've seen some "TV" shots from a camera sitting there and sliding above the pool following the competitors, there are quite regular "pool theater" performances using quite some decorations hung from the ceiling (so where that portal was used to install and after the show remove them)

So in case the pool has something like that already installed (or it is planned if the pool does not exist or is not complete yet), the light fixtures straight above the pool should not be problem at all - the servicing then has nothing to do with the water at all.
But that bridge/portal is quite deeper investment than just the lighting (just the lighting wouldn't justified such portal, I guess), if it makes sense mainly depends on the expected use of that pool, if there are expected activities making use of it...

But definitely the lighting just straight above the pool water with larger pools is the most frequent location even when there is no special access equipment at all. Usually in the form of few high-bay high power HID's (a 6 lane wide, 50m pool has just 4 of such lanterns there, I would guess on some kind of winch mechanism to lower them down for servicing). Smaller pools will suffice with even fewer of them.

Another way to replace high bay fixtures above a pool is to make the pool large enough to have a boat come for replacement of the lamps, and have a dry surface for the lamp replacers.

The weight of anyone standing on a ladder moves the center of mass up, this would tip over into the water

Would be easier to make a ladder out of isolating material and put that in the water, then "walk with the ladder" to go through all the luminaires without going down into the water

The weight of anyone standing on a ladder moves the center of mass up, this would tip over into the water

Would be easier to make a ladder out of isolating material and put that in the water, then "walk with the ladder" to go through all the luminaires without going down into the water

Don't worry, you can just have boat attachment areas to stop the center of gravity from getting you.
And are you talking about while at the top of the ladder, move your body so the ladder starts walking? Sounds unsafe.

Better than a ladder on a boat..

Another thing, I went underwater, and I saw that small textures look completely blended together, so if they were all little LEDs, the glare would be severely reduced, as you will not see a bunch of little dots, and instead see a solid light.
We also have to consider the water light absorption, an incandescent pool light makes everything turn a strange fluorescent blue-yellow-green. I think of it as putting a clear MV in the pool.

The light source reflects from the water when you are above the water, or you can see it through the water when you are underwater looking up. And swimming on the back means that you stare directly into the luminaires. No place for individual chip LEDs there as the glare will be the same as looking at them directly, or worse (the moving water makes random curved mirrors on its surface that occasionally focus the light, so you see some of the same dots amplified)

And if you use pool glasses, then at the moment when they fog up they will start refracting the light at some angles - There you'll see on some edges the separate spectral components of the light, and once again i thing the LED would not be all that great (it got basically 2 powerfull spectral lines, compared to more lines less powerfull each in discharges)

The light source reflects from the water when you are above the water, or you can see it through the water when you are underwater looking up. And swimming on the back means that you stare directly into the luminaires. No place for individual chip LEDs there as the glare will be the same as looking at them directly, or worse (the moving water makes random curved mirrors on its surface that occasionally focus the light, so you see some of the same dots amplified)

And if you use pool glasses, then at the moment when they fog up they will start refracting the light at some angles - There you'll see on some edges the separate spectral components of the light, and once again i thing the LED would not be all that great (it got basically 2 powerfull spectral lines, compared to more lines less powerfull each in discharges)

Now the idea of LED is making me shiver!
You could at least diffuse them, LED and HID.
And what about the high CRI LEDs, with more spectral lines?

Still not better than HID or FL, even lower CRI HID or FL (think standard Triphosphors)