[Tangman]

Two things that I noticed from the pics. and from Mark said, as there is no check valve in the return plumbing, I would suggest a siphon break, a drilled hole just above or right at the water line in the main tank on the return line and i would relocate the electrical power bar away from the top of your skimmer, because if your skimmer were to over flow ( and they do ) it looks like the power bar would get very wet.