Hey guys, I'm new to this forum and to the planted tank scene. I have a 55g and I've chosen to go with eco-completer substrate. I've been doing a lot of research and there's a few things I'm not clear on. I know I need about 3" inches ideally and I've seen the 20lb/10g rule, but is that enough to reach a 3" depth with 6 bags. I found a substrate calculator that said I needed 160 something lbs. but that's more than the rule of thumb calls for. So if anybody could help clear the confusion then that woul be awesome. Thanks everyone for any help or advice.