I loved the look of sand till I had it in my 75 gallon tank for a few months. It was impossible to clean or vaccuum it properly. Then it started to stink and the water took on a yellowed tinge. I did 50% water changes weekly, and cleaned the tank faithfully. Nothing worked, so I ended up tearing the tank apart and removing all the sand (not an easy feat). There was a nasty gray layer toward the bottom level of the sand that smelled terrible.
I changed the substrate to crushed coral and I would NEVER go back to sand! I love the look of the coral, and it is as easy to clean/vaccuum as gravel. Now the tank stays crystal clear with no odors.