A friend from work, followed me home today with a 55 gal tank. After he left, I measured the tank. It measured 18 x 48 x 21. I googled tank measurements......It's not a 55.....It's a 75 and I'm thrilled to death! Gave me a metal stand also, which is my next project to sand down and repaint. I need suggestions....what is the best substrate for the bottom? All my existing tanks have crushed coral. I have 3 tanks with no creatures in it with enough crushed coral and decorations to set this tank up immediately and they are seasoned and ripe for an octopus but do I want to do crushed coral again or go with something different? All I need is a hood and possibly another filter of some type as I have a large enough protein skimmer and a large Eheim that used to run my 47 pentagon. I'm so excited....won't be long now!