Mike....if I'm going through something on the thin size, I use a male and female pvc adapter from the ELECTRICAL dept...the threads are straight. They will screw almost 100 % together...just make a rubber gasket or use 'silicone'
Some people fuss about gray PVC.

Aquatic eco systems has several different types, sizes and materials of bulkheads.
I use the 'economy' bulkheads...a 2 inch, is around 8 bucks

I've used uni-seals too.


EDIT:
LOL....should of checked your link...before responding.
Wow...they have lots of stuff.
Wonder how bad the postage would be...they gave their hours of operation in PST
I'm spoiled...I can drive to Aquatic Eco....