Bulkhead2 ?

[mitlik1]

I am looking to drill a 20 gallon glass aquarium for bulkheads. I have the drill bit that make a hole size of 1 3/4" for 1 " bulkhead. I see that there are standard bulkhead fitting and double threaded bulkhead fittings. Do most people just get the double threaded? Also, I have seen they have the heavy duty bulkheads. What is the difference between heavy duty and just plain bulkheads? The same hole would fit a 3/4 inch bulkhead (more plastic?).

 

[geo]

The heavy duty fittings are probably of a thicker material and will not work with the 1.75" hole size you have. The standard bulkheads work fine. I normally try to use the threaded fittings when I can. It allows for the plumbing to be removed without damage to the fitting.