Yep 2" for the 2 90^, you'll have to dremel out the inside a little as they don't fit over the 2.5" od pipe. It's actually not a bulkhead, just a abs fitting i found that has a slip fit on one end and a thread on the other. The slip fit goes through the acrylic and the 90^ slipps over, gule all this even the acylic to abs with weldon 16. Or ou can spend the extra $12 and go with a 1.25" bulkhead.
Still foaming like mad just not pulling out a bunch as it's on a 25gal rock tank with 5 frags and 25lbs of cured LR and a recent 75% water change (had some hair alge, no skimmer :P ). Pretty much no bio load, need to get some fish in there and see what it does. It's still putting out simmate just not really dark.
Clinton