I have three oscars 10", 11", and 7" and a 16" clown knife in a 75 gallon. Soon will be upgrading them to a 180 gallon. For now there in the 75 gallon with white sand. I'm thinking about taking out the sand and not putting any in the 180 gallon. because it gets so murky and gets in the filters etc.. Has anyone had experience with an aquarium with a bare bottom? Is there any drawback? other than the looks of course.