with screw on bulkheads, it's generally advised to not use any compound/tape. The seal is on the inside of the tank where the gasket is, the threads merely serve to tighten those two surfaces together. (the glass and rubber gasket)
Using compounds, etc only makes it harder to get apart later if you need to repair, and the harder it is to get apart, the more likely you are to break something. Just clean the glass and gasket REALLY well and wipe them down with alcohol or similar and you'll be just fine.
by the way, super jealous.
*edit* I think I misunderstood. Were you talking about using pipe dope on the threaded fittings for your loc-line and drain pipes? If so, then that makes more sense. I thought you were talking about for tightening up the bulkhead.