What is the best color to paint my swimming pool so it will be warmer? I assumed dark blue, but would silver be better?

My pool is an inground fill & drain with no filter, pump, or pool cover. The edge of the pool is about 2 feet above ground.

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henster226 years ago
I say black as it will absorb the warmth and will slowly give off the heat.
lemonie8 years ago
Contrary to other comments, if it is the water you want to heat up, a reflective surface might be better. The water will absorb some radiation on the way in and some more when it is reflected back out.
Then again, making the pool walls and floor dark will help them absorb heat, which should transfer through conduction to the water.

How about building a solar heater instead?

jtobako lemonie8 years ago
If the light is reflected threw (and out of) the water, a reflective bottom is counter-productive. If the water is tinted to absorb the light coming in and being reflected from the bottom, that's different : )
lemonie jtobako8 years ago
Tinted water, mmm any suggestions?
Carbonated pool-water..?

. No data to back it up, but intuition tells me that his best bet is to paint everything a dark color. It doesn't seem to me that clear water absorbs all that much light energy (anecdotal).
. Tinting may help, but a dark enough tint to do any good may not be very aesthetic. Probably going to be difficult to find a tint that will hold up to the tri-chloro and not stain everything, including bathing suits and skin. Just guessing.
. What would carbonated water accomplish? Does the CO2 absorb more energy?
. CO2 escapes very quickly and might react with some of the other chemicals.
. You're a Chemist. Let's see ... there will be Cl and CN in various forms ( TCCA ). Not sure what other chemicals are used - Cl-/Br-based seem to be the most common.
CO2 absorbs strongly in the infra-red (it's a long time ago but 2200 -2400 wave numbers?). I was thinking of a "fizzy" pool, and hoped you'd see that as non-serious. But buffered with bicarbonate maybe?

I still reckon the solar-pool-heater is a good plan

jtobako lemonie8 years ago
A solar water heating (rather than heater) system might be a place to start looking to see if a dye might help.
merryk (author) 8 years ago
I treat the pool with tri-chloro and a softener and drain it as required. Because I don't have a pump, I can't put in the solar heater that was suggested. So the consensus is a dark color? Thank you all for your replies!
jtobako8 years ago
You want the pool to absorb light, not reflect it. Black would be best, reflective worst for heating the water. How do you control algae and such without a filter?
For our fish pond, we used a blue dye to reduce the effective light hitting 'all' the water so algae wouldn't flare up - not so good for a swimming pool, but the water definitely absorbed more energy.
. IIRC, forest green is better than black for absorbing sunlight, but a Q&D search didn't turn up anything one way or the other. Something to do with the spectrum of sunlight.
Yeah, black is the way to go if you want something to get warm. Dark colors don't reflect as much light as light ones, and thus absorb it converting it to heat.