People often ask me what would be perfect, how should I plumb the pond, what hardware is needed. Well, the answer is "Don't cut your liner for a bottom drain." And then, do everything in two inch PVC whether that's hard PVC or soft pool hose pipe. Here's some images to look through to design your pond and the plumbing system.
+ Perfect liner pond, how to dig it. + Perfect plumbing, schematic aerial view + Perfect intake system with skimmer and bottom drains
+ Using a "too strong" Sequence pump for small (850 gallon) ponds. + Taming a monstrous submersible pump + Flooming a pond for maximum aeration

Now, you may already know that you can get the whole Enchilada in one go, we offer a Cadillac 2.2 and a Cadillac 4.4 system with all this plumbing included. Check them out: Cadillac 2.2 - Cadillac 4.4