Write-Up Wednesday: Schedule 80 Bulkheads

Aquarium bulkheads come in two flavors:

  • sch40
  • sch80

“sch” (short for “schedule”) refers to the thickness of the plastic used in PVC plastic parts. The bigger the schedule, the thicker the plastic and the more pressure that the pipe can hold. It makes sense then that a sch80 bulkhead is beefier than a sch40 bulkhead. Usually a lot beefier.

Take a look at these two bullkheads. The black sch40 bulkhead is on the right and the gray sch80 bulkhead is on the left. You can clearly see how much beefier the sch80 bulkhead is than the standard sch40 bulkheads supplied with most aquariums. Also note how much thicker the rubber gasket is.


While the sch80 bulkhead is beefier, the added strength isn’t needed around saltwater tanks. The pressure in an aquarium PVC pipe is very low and you won’t even get close to blowing out a sch40 bulkhead or pipe. Also note that if you break a sch40 bulkhead, you are over tightening it or putting too much pressure on the bulkhead with the attached pipe. In other words, you’re doing something wrong!

If the added strength isn’t needed why do hobbyists use sch80 bulkheads? Sch80 bulkheads are used when hobbyists are looking for a beefier look or are using sch80 pipe (again not needed) and want to maintain the all-gray look. Basically, it’s a matter of taste.

Oh, if someone tells you that you have to use sch80 bulkheads or else you’ll have leaks, let me know so I can add it to my “Terrible Advice Tuesdays” posts!

Browse the Store! Questions?

Comments for this article (4)

  • tony herbert says:

    just a point. remeber some bulkheads reduce the flow by as much as 30%. so if you use a thicker walled bulk head remeber to oversize your hole to allow for this. the sch40 with a right angle fitting reduces your flow by 35%.
    i always use waste pipe bulkheads and fittings. these only reduce your flow by 8%

  • George Barsi says:

    Can you provide an example of a waste pipe bulkhead? Just curious if it is different than the Schedule 40 bulkhead as pictured above.

  • George…for drain lines I use the same type of bulkhead as pictured above

  • Steve Dodd says:

    Hi Mark , I am a little concerned about the new Write up Wednesday feature as this and other emails I have received from you all seem to be pushing people toward your facebook page.
    Please remember that not everyone is on , or whats to be on , facebook.
    Also remember that this is a organisation that collects , stores , and sells data on individuals to insurance companies , banks , prospective employers , ect.
    I , along with millions of others , have no intention of joining a orgaisation like that.

    Sorry to get serious but I would hate to lose the knowledge that you give out

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.