03-27-2011, 10:53 AM
I agree about using the time of day as a sunscreen, anytime within 3 hours of sunrise / sunset is safe even for my pasty white skin without chemical magic creams.
As to the "ecosystem" - even if it is a manmade swimming pool, there are lots of living creatures in there, and it's a shame to give them the old BP/Valdez challenge if you don't have to.