nice build. Building your own from scratch is much more rewarding. I love building the tanks that when i finish one i'm itching to build another just to try a new background technique. My first one i used styrofoam insulation. The build i'm working on now i used styrfoam again plus GS foam to foam in my pots. I did my drains a little different than you though. I orginally had straws in there as drains, but then took them out and just bored the hole out bigger with a grinding stone attached to my drill. I was afraid the tiny hole of a straw may get clogged too easy.