Bulkheads & Uniseals
Bulkhead fittings create a secure, watertight connection between your aquarium, overflow, sump, and plumbing system. Bulk Reef Supply carries black ABS aquarium bulkheads in popular sizes and configurations, including Slip × Slip, Slip × Thread, Thread × Slip, and Thread × Thread.
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.
Important: These dimensions apply to the listed Bulk Reef Supply ABS bulkheads in all configurations. Always verify the required installation-hole size on the individual product page before drilling.
| 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 | 30 mm |
| 3/4" ABS Bulkheads | 52 mm / 2.04" | 50 mm / 1.98" | 34 mm / 1.33" | 35 mm | 35 mm |
| 1" ABS Bulkheads | 68 mm / 2.67" | 63 mm / 2.48" | 42 mm / 1.65" | 45 mm | 45 mm |
| 1-1/4" ABS Bulkheads | 77 mm / 3.05" | 71 mm / 2.80" | 51 mm / 2.00" | 53 mm | 53 mm |
| 1-1/2" ABS Bulkheads | 86 mm / 3.38" | 73 mm / 2.87" | 59 mm / 2.32" | 60 mm | 60 mm |
| 2" ABS Bulkheads | 98 mm / 3.85" | 73 mm / 2.87" | 72 mm / 2.83" | 75 mm | 75 mm |
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