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-slip |
|---|---|
| Aquarium Type | Saltwater, Freshwater |
| Size / Diameter | 1/2 in., 3/4 in., 1 in., 1 1/2 in., 2 in. |
| Connection Type | Slip (socket) |
| Fitting / Part Type | Bulkhead |
| Form | Rigid (hard PVC) |
| Color | Black |
Write Your Own Review
Product Questions
What size hole saw for 2 inch bulkhead
Question by: Chris on Mar 10, 2026, 10:49 PM
It can work in a hole 98mm/3.85" to 72mm/2.83"
Answer by: Matt Lucero (BRS Staff) on Mar 11, 2026, 9:05 AM
What type of glue do you recommend for the slip bulkhead and PVC pipe?
Question by: Jacob on Feb 4, 2025, 2:24 PM
We generally use Oatey PVC primer and cement.
Answer by: JJ K (BRS Staff) on Apr 27, 2025, 7:35 AM
I have a pre-drilled tank that came with barbed bulkheads and I am converting to slip. I need a 1" I/D (inside diameter return) and a 1-1/4" I/D supply. The diameters listed do not specify inside or outside according to conventional plumbing. Thanks for your help.
Question by: david marcinkewicz on Jan 11, 2017, 7:12 PM
Great question! The bulkhead sizes will match the size of SCH40 or SCH80 PVC pipe you intend to use. So, if you plan to hard plumb the aquarium with 1" PVC, you would need a 1" bulkhead. :-)
Answer by: Randy on Jan 12, 2017, 3:32 PM
Do these bulkheads include the rubber gaskets as well?
Question by: John on Jul 7, 2016, 8:53 PM
Hi John,
All of the ABS Bulkheads come with a gasket to create a leak free seal.
If you have any other questions just let us know.
All of the ABS Bulkheads come with a gasket to create a leak free seal.
If you have any other questions just let us know.
Answer by: Charlie on Jul 8, 2016, 7:24 AM
Do these bulkheads come with the required wrench? If not, where can I purchase one?
Question by: alex razo on Jul 3, 2016, 5:46 PM
No,
There is no need for a wrench with a bulkhead. it can be hand tightened and with standard channel locks or other tools tightened down further.
There is no need for a wrench with a bulkhead. it can be hand tightened and with standard channel locks or other tools tightened down further.
Answer by: Connor on Jul 6, 2016, 12:44 PM
I have a 75 gallon tank that's going to have a 660GPH return pump and RSS18 large overflow box. How do I determine what size plumping is appropriate? I plan on having a main overflow and an emergency overflow.
Question by: Mel on May 31, 2016, 8:39 AM
Great question!
With a return pump of 660 GPH we recommend using 1 inch drain lines. This means 1" bulkhead and 1" pipe will be a great fit! The 1" has a gravity fed flow up to 650 GPH and by the time your return pump pushes up the head height the flow into your tank will be well under 600. Feel free to let us know if you have any further questions!
With a return pump of 660 GPH we recommend using 1 inch drain lines. This means 1" bulkhead and 1" pipe will be a great fit! The 1" has a gravity fed flow up to 650 GPH and by the time your return pump pushes up the head height the flow into your tank will be well under 600. Feel free to let us know if you have any further questions!
Answer by: Connor on Jun 8, 2016, 12:19 PM
What is your recommended "reef safe" solvent to join PVC pipe to ABS slip bulkheads?
Question by: Ken Smolana on Apr 3, 2016, 4:56 PM
Great question!
You will use PVC to ABS transition cement. Currently one option from many hardware stores is Oatey Green. Feel free to let us know if you have any further questions!
You will use PVC to ABS transition cement. Currently one option from many hardware stores is Oatey Green. Feel free to let us know if you have any further questions!
Answer by: Connor on Apr 6, 2016, 12:33 PM
Which bulkheads will i need ? Im doin 1"pvc in overflow and 3/4" pvs from pump. Which bulkheads will fit these pvc sizes?
Question by: dan on Jul 31, 2014, 5:44 PM
Hi Dan,
If you have a 1" PVC pipe you would want the 1" bulkhead for that pipe and 3/4" bulkhead for 3/4" pvc.
If you have a 1" PVC pipe you would want the 1" bulkhead for that pipe and 3/4" bulkhead for 3/4" pvc.
Answer by: Bulk Reef Supply on Jul 31, 2014, 5:44 PM
Will a 1/2 inch PVC pipe fit in the inside diameter of the 1/2 bulkhead? Or is the inside diameter of the 1/2 in bulkhead exactly 1/2 inch? If that is the case will a 1/2 inch PVC inside connector fit in this bulkhead? Thanks
Question by: jimmy on Jul 9, 2014, 8:12 PM
Hi Jimmy,
All the plumbing sizes are nominal, so a 1/2" PVC pipe will fit in a 1/2" ABS bulkhead no problem.
All the plumbing sizes are nominal, so a 1/2" PVC pipe will fit in a 1/2" ABS bulkhead no problem.
Answer by: Bulk Reef Supply on Jul 9, 2014, 8:12 PM
Hello
I just bought some bulkheads.
1) 1 1/2" ABS Bulkhead Slip X Slip Dimensions
2) 2" ABS Bulkhead Slip X Slip Dimensions
I need to drill holes for these bulkheads. There are A, B, C hole sizes. Which one do I use for acrylic? These hole saws are all a little different and I want to make sure I choose the right hole saw.
Thank you!
I just bought some bulkheads.
1) 1 1/2" ABS Bulkhead Slip X Slip Dimensions
2) 2" ABS Bulkhead Slip X Slip Dimensions
I need to drill holes for these bulkheads. There are A, B, C hole sizes. Which one do I use for acrylic? These hole saws are all a little different and I want to make sure I choose the right hole saw.
Thank you!
Question by: Tanner on Apr 23, 2014, 4:28 AM
Hi Tanner,
The ABC are dimensions, not hole sizes :) Dimension C is the size of the part that goes through the tank so you need to make sure the hole is that big, but not larger then A or B which is the size of the head and the nut. Generally speaking you want to go with the closest size drill bit to dimension C that is at-least the size of dimension C.
The ABC are dimensions, not hole sizes :) Dimension C is the size of the part that goes through the tank so you need to make sure the hole is that big, but not larger then A or B which is the size of the head and the nut. Generally speaking you want to go with the closest size drill bit to dimension C that is at-least the size of dimension C.
Answer by: Bulk Reef Supply on Apr 23, 2014, 4:28 AM
Login and Registration Form