Haha, this thread..... Not at the OP, but at some of the posts. Op.... I don't know what type of HOB filters you have, but youll have more surface agitation on the back of the tank than you will from haning them on the sides. The biggest part about moving fish tanks and breaking/cracking glass and seams is when the tank is on a twist. Just make sure you try to apply even pressure when moving it and you should be ok. As far as water changes, there is no cookie cutter guide to the amount of water needing to be changed a week. That all depends on your stock list and filtration. If your water parameters are good at 25% a week and your water is clear and your happy and the fish are happy, then dont fix what's not broke. If your media in your filters have been established, you should have no prob draining a large percentage of water to move the tank. Just try to do everything you can to prevent the fish from being stressed. Just take normal precautions like you do during any water change! I sort of did the same thing when I set up my 150. I planned to have 2 canisters and a hob, well, I set the tank too close to the wall and filled it up before I had the HOB on there! Luckily my canisters are still plenty for filtration.