Tech Tank Bulkhead Hole Size?

[bstaylor]

I have a 120 tech tank, what is the size of the bulkhead hole, all four are the same size, I want to hard plumb my tank, so I need to purchase new bulkheads, that are slip/thread.

Thanks

 

[AcroporAddict]

The 120 Tech Tank has holes for four 1" bulkheads, which means if you are going to use 3/4" pipe for your return, you will need to reduce at your return connection points. You may want to order two slip/slip 1" bulkheads and just reduce them as needed for the return piping.
Dave