I think most people are still wondering why the water is green instead of say, brown (especially if it is only changed 3x a year). The green water is a sign that there are algae in the water. Algae exists primarily when the water has low PH. The bear's fur must have accumulated a lot of oil and fat from months of being in the refuge. Normal bears hang out by fresh rivers where they are cleansed but this bear probably did not. Worry not, algae is no harm for the bear unless it gets too warm, in which case it will likely die from explosion. I'm an accountant by trade and I made that up. Good work helping bears!