Hopefully I'll get to my plumbing this week or next but have a few questions. My tank came with the Marineland bulkheads, they have a sort of teeth that rest against the bottom glass and doesn't sit flat. I was thinking about getting bulkheads that will sit flush with the glass, is that a better idea? Also what type of bulk head should I get, slip/slip or slip/thread(on the bottom). I was think the later so I could use a threaded PVC adapter because I'm sure you don't want to glue your drain (or return) directly to the bulkhead?