Just a circulation questions, I've found someone on craigslist selling 3 marineland 660s for $8 a piece. I have a 55 gallon tank and plan to have coral, but I've only ever used Koralias, so I know nothing about this kind. Granted that they're in good shape, is that a good price. Any pros and cons comparing Koralias to the marineland....Do they hang off the side of my tank or can I position them where I want?