We have one of those waterers for our dog that you fill the 5 gallon water bottle. The kind that you tip over. She can drink that much water in a few days but at the bottom there is pink algae growing in it. I can't seem to figure out how to clean the bottle out. What do you all do? A baby bottle brush is too short and can't twist around the edges. I filled it with a solution of bleach and water and let it sit but that didn't help either. So, now I"m filling a bowl lots and lots and lots and lots. I want the bottle system back in order. I know others have these water bottle setups.