Bulkheads create a secure, watertight connection through the wall of an aquarium or sump, allowing plumbing to safely move water in or out of the system. These low-profile, reef-safe bulkheads are made from durable black ABS plastic and feature a slightly thicker construction than many standard aquarium bulkheads for added strength and reliability.
How Do I Pick the Right Bulkhead for My Project?
Threaded vs. Slip Connections
Bulkheads are available with either threaded or slip connections for attaching plumbing.
- Threaded: Threaded fittings screw directly into the bulkhead for a semi-permanent installation. Threaded connections make future plumbing changes easier, but they can sometimes increase the chance of a leak.
- Slip: Plumbing fittings or PVC pipe are glued directly into the bulkhead for a permanent installation. Slip connections are often the most robust option for long-term use.
What Size Bulkhead Do I Need?
When selecting a bulkhead, the hole in your tank must be slightly larger than the corresponding bulkhead’s “C” measurement, but no larger than the “A” measurement. See the diagram for reference.
Example: If your tank currently has a 1.75" diameter hole, you would want to use the 1" ABS Bulkhead.
Bulkhead and Glass Drill Bit Sizing Guide
Use the chart below to compare ABS bulkhead dimensions and match each bulkhead with the correct diamond-coated glass drill bit. Bulkheads are identified by the size of pipe they connect to—not by the larger diameter of the hole drilled through the aquarium.
The dimensions below apply to all slip & thread configurations.
| Bulkhead | A — Head Diameter | B — Full Height | C — Body Diameter | Hole Size | Glass Drill Bit |
|---|---|---|---|---|---|
| 1/2" ABS Bulkheads | 44 mm / 1.72" | 43 mm / 1.69" | 27 mm / 1.06" | 30 mm / 1.18" | 30 mm |
| 3/4" ABS Bulkheads | 52 mm / 2.04" | 50 mm / 1.98" | 34 mm / 1.33" | 35 mm / 1.38" | 35 mm |
| 1" ABS Bulkheads | 68 mm / 2.67" | 63 mm / 2.48" | 42 mm / 1.65" | 45 mm / 1.66" | 45 mm |
| 1-1/4" ABS Bulkheads | 77 mm / 3.05" | 71 mm / 2.80" | 51 mm / 2.00" | 53 mm / 2.09" | 53 mm |
| 1-1/2" ABS Bulkheads | 86 mm / 3.38" | 73 mm / 2.87" | 59 mm / 2.32" | 60 mm / 2.37" | 60 mm |
| 2" ABS Bulkheads | 98 mm / 3.85" | 73 mm / 2.87" | 72 mm / 2.83" | 75 mm / 2.96" | 75 mm |
| SKU | brs-bulkhead-abs-thread-thread |
|---|---|
| Aquarium Type | Saltwater, Freshwater |
| Size / Diameter | 1/2 in., 3/4 in., 1 in., 1 1/4 in., 1 1/2 in. |
| Connection Type | Threaded |
| Fitting / Part Type | Bulkhead |
| Form | Rigid (hard PVC) |
| Color | Black |
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Product Questions
I have an acrylic 55g hexagon tank and the drain is pre-drilled to 3/4". Is this ok, or should I attempt to drill it to 1"? Also, what are the benefits to using sch80 vs. ABS bulkheads?
Question by: GUSTAVO MARTINEZ on Jun 28, 2016, 8:58 AM
Good question,
We would not attempt to drill again if the hole is 3/4" in the acrylic you can use the smaller size bulkhead. Schedule 80 and ABS do not have a difference on most tanks and we recommend ABS as it is a more universal size however Sch. 80 is rated for higher pressures.
We would not attempt to drill again if the hole is 3/4" in the acrylic you can use the smaller size bulkhead. Schedule 80 and ABS do not have a difference on most tanks and we recommend ABS as it is a more universal size however Sch. 80 is rated for higher pressures.
Answer by: Connor on Jun 29, 2016, 6:28 PM
I am going to drill through glass to install my overflow and return. I was wondering what size hole is adequate for a Quite One PRO 4000 (1022 gph - 5 vertical feet) to over flow into without causing too much constriction when exiting the display. Also should I need two overflow holes or one?
75G display + 20G sump. Do you recommend a different pump? Thank you.
75G display + 20G sump. Do you recommend a different pump? Thank you.
Question by: Peter on Apr 22, 2016, 7:12 PM
Great question!
We recommend at least 2 overflow drains coming down with two 1" drain lines. additionally larger drains can work up to 1.5" drain lines. The 4000 pump will work great on that system!
We recommend at least 2 overflow drains coming down with two 1" drain lines. additionally larger drains can work up to 1.5" drain lines. The 4000 pump will work great on that system!
Answer by: Connor on Apr 27, 2016, 4:10 PM
So I have a 3/4 overflow bulkhead from lifeguard aquatics and a 1/2 return, I purchased two 90 degree barb X female threaded pieces from you guys, one is 1/2 in and the other is 3/4 in, but they are too small to fit on the male threads of the bulkheads, should I have got a size up?
Question by: Luke on Mar 25, 2016, 1:14 PM
Great question!
You did buy the correct size however the only flaw is that you are attempting to thread onto the outside threads of the bulkhead. Unfortunately nothing threads onto the outside threads of the bulkhead except the nut. All plumbing will be glued or (male threaded) on the inside diameter of the bulkhead. If the inside of your bulkhead is smooth you will need a Spigot x Barb fitting to be glued in (If it is threaded on the inside diameter you can use male NPT x Barb. I have included the links below.
https://www.bulkreefsupply.com/gray-male-pipe-adapter-spigot-x-barb.html
Or:
https://www.bulkreefsupply.com/schedule-80-straight-barb-x-male-thread-1-4b880d619bbbcbbea22b13bfa30a1ace.html
You did buy the correct size however the only flaw is that you are attempting to thread onto the outside threads of the bulkhead. Unfortunately nothing threads onto the outside threads of the bulkhead except the nut. All plumbing will be glued or (male threaded) on the inside diameter of the bulkhead. If the inside of your bulkhead is smooth you will need a Spigot x Barb fitting to be glued in (If it is threaded on the inside diameter you can use male NPT x Barb. I have included the links below.
https://www.bulkreefsupply.com/gray-male-pipe-adapter-spigot-x-barb.html
Or:
https://www.bulkreefsupply.com/schedule-80-straight-barb-x-male-thread-1-4b880d619bbbcbbea22b13bfa30a1ace.html
Answer by: Connor on Mar 28, 2016, 10:53 AM
I recently purchased these for an overflow. I also purchased schedule 80 elbows. Is it ok for ABS to be connected to schedule 80 with threads?
Question by: Mark on Mar 11, 2016, 6:57 PM
Great question!
Schedule 80 threads will work great with an ABS bulkhead. You will want to ensure that plumbers or Teflon Tape is used to ensure a water proof seal. Feel free to let us know if you have any further questions!
Schedule 80 threads will work great with an ABS bulkhead. You will want to ensure that plumbers or Teflon Tape is used to ensure a water proof seal. Feel free to let us know if you have any further questions!
Answer by: Connor on Mar 14, 2016, 10:37 AM
for 3/4 and 1 inch bulk head s- 40 what size male fitting go inside this bulk head
Question by: michael on Mar 4, 2014, 4:24 AM
Hi Michael,
If you have a threaded fitting then a 3/4" male threaded and 1" male threaded fitting would go into the 3/4" and 1" bulkheads respectively.
If you have a threaded fitting then a 3/4" male threaded and 1" male threaded fitting would go into the 3/4" and 1" bulkheads respectively.
Answer by: Bulk Reef Supply on Mar 4, 2014, 4:24 AM
Im not sure what kind of bulkheads I need or the difference between them aside from size
Question by: Tyler on Jan 21, 2014, 6:30 AM
Hi Tyler,
A slip fitting is one that you insert a pipe into and then glue. A threaded fitting is one that has threads and is screwed together with another threaded fitting. A pipe wont go into a threaded fitting and vice versa so which bulkhead you get really depends on what type of fitting you plan to connect to it. If for example you want a threaded strainer on one side and a threaded barb connection on the other, a thread x thread bulkhead would be what your looking for.
A slip fitting is one that you insert a pipe into and then glue. A threaded fitting is one that has threads and is screwed together with another threaded fitting. A pipe wont go into a threaded fitting and vice versa so which bulkhead you get really depends on what type of fitting you plan to connect to it. If for example you want a threaded strainer on one side and a threaded barb connection on the other, a thread x thread bulkhead would be what your looking for.
Answer by: Bulk Reef Supply on Jan 21, 2014, 6:30 AM
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