I have a 55 gallon tank which has gravel in it..I'm thinking about changing it out and doing sand. I love the look, but I have a HOB filter..which i'm worried about getting clogged with sand. I could always do a low spot where my intake is, but I'm looking for some advice. Anyone done gravel to sand with a HOB filter? If so, how difficult is it to change the gravel out without taking all my fish out? Also, How much sand would I need to create a nice layer on the bottom? And would I still be able to use my 25ft water changer for cleaning or is this going to be too strong and suck up the sand? Any advise/input is appreciated! Thanks!!