Quote Originally Posted by waterbear View Post
my biggest concern with a "natural pool" would be the "brain eating amoeba", Naegleria fowleri, that exists in warm bodies of water such are found in Florida, Texas, and other subtroipcal to tropical areas. It has also been found in unchlorinated swimming pools!

Most of the cases in the US reported to the CDC have occurred in southern states like Florida, Texas and Louisiana and most have occurred by people swimming in lakes but there is a case in Orlando where a young man died after contracting it at a Water Park Orlando Watersports Complex)!

Natural pools depend on the same types of bacterial and plant based biopurification processes that lakes do so I would be very cautious about their REAL safety!

The Wikipedia article pooldoc linked discussed the importance of keeping a natural pool temp below 82f in order for the good bacteria to stay on top of the bad ones. I bet in FL, it's pretty hard to keep a natural pool below 82f in summer. I know my chlorine pool gets into the 90's on it's own... Heck, I saw 78f (water temp) last week and it's still February!

I'm guessing that's part of the reason they are so much more popular in EU.