Hi, I'm about to get a 55 gallon tank that has had a turtle in it. As far as I know, it doesn't leak. It's filled halfway for the turtle. I have two questions: If it doesn't leak halfway, should I still test for leaks at 100%? And second, since turtles are messy, and I saw a nice chunk of algae in the tank, what steps should I take in cleaning the tank to reduce possible algae contamination?