(I can't edit my previous post again, sorry)
After looking at some pictures and some of BauriBob's videos, I have answered the question of how to weight it down and the rough idea of what I need. I see he uses zip ties, and I'll be sure to pick some up as well as maybe sand.
The only thing that I can think of is do you use any glue or seakans on in the elbows and bends of the pipe? Will the aquarium safe crazy glue be fine or should I use like an aquarium silicone?

As it stands now this build is a lot chwache than I would have thought. I should have some money left over for a nice chunk of wood !