Both pools had multiple freshwater springs flowing in. You can see the water flow from one such spring near the crack on the left of this picture. This caused both a very strong and thin thermocline in the pool along with a strong salinity change - cold fresh water was on the bottom, and warm salty water on top. The water was very clear above and below this layer, but everything is strongly distorted in the boundary layer. It was a very interesting effect, like I just woke up with a lot of crap in my eyes where everything looks blurry.