OK guys, give me the lowdown on the foam under acrylic tanks. I got my big 380 in place over the weekend. My stand is like 42" high, so the tank (36" high) will be right at eye level. My question is the foam that goes under the tank. It scooted back about an inch and a half. I am going to cut the excess off the back and place back up front. But what is the real purpose of the foam?