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PVC solvent-weld tank connector, 32 or 40 mm
Regular price
$14.76
Regular price
Sale price
$14.76
Unit price
/
per
$4.92 × 3 with no fees
Klarna.
This bulkhead fitting passes through the wall of a tank, a vat or an aquarium to carry a PVC pipe. It is tightened with a nut and a seal, and the pipe is glued into it.
The bulkhead fitting comes in two sizes: 32 mm pipe for a 43 mm hole, 40 mm pipe for a 54 mm hole.
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The summary
- Which size: 32 mm pipe for a 43 mm hole, 40 mm pipe for a 54 mm hole.
- How it is held in place: a nut clamps the body against the wall, and a seal makes it watertight.
- Which wall: plastic tank, IBC tank or glass aquarium that is already drilled.
- How to connect the pipe: the PVC pipe is glued into the body.
Draining water from a tank through the wall, without leaks
To drain a tank from the bottom, to make a tank overflow to a filter or to connect two tanks through the side, you need to pass through the wall without it leaking. The tank connector consists of a flanged body, a seal and a nut: the body passes through a hole drilled in the wall, the nut tightens it from the other side, and the seal ensures watertightness.
🔧 Drilling in the right place
The hole is drilled with a hole saw of the exact diameter: 43 mm for the 32 mm bulkhead fitting, 54 mm for the 40 mm one. Choose a flat part of the wall, away from corners and ribs, and leave a few centimetres of margin around the hole so that you can screw on the nut. On a glass aquarium, drilling calls for a water-cooled diamond drill bit, and a glass professional can do it for you.
Sharing the tank water with a 32 mm tee
With the 32 mm tank connector, a solvent-weld PVC tee of the same diameter, glued onto the outlet pipe, splits the water between two destinations, for example two grow beds, or one grow bed and the return to the filter. The whole circuit then stays at the same diameter, and you add no reducer that would restrict the flow.
Tighten the nut by hand, no tools needed
A nut tightened with a spanner crushes the seal, which then no longer keeps the connection watertight, and the wall of your plastic tank may crack around the hole. Screw the nut on by hand until you feel firm resistance, then give it a further quarter turn.
📏 32 or 40 mm
The diameter is chosen according to the flow that has to pass through the wall. A 32 mm tube is enough for a grow bed fed by a small pump, while a 40 mm one lets a stronger flow through without the level rising in the bed. For an overflow, always choose a larger size than the water inlet, because an outlet that drains less than what comes in lets the level rise until it overflows.
Grow bed
The bulkhead fitting drains the tank from the bottom, towards the fish.
IBC tank
On an IBC tank, the bulkhead fitting creates a side outlet to the filter or the pump.
Overflow
Fitted at the top of the wall, the bulkhead fitting drains off excess water.
Drilled aquarium
A glass drilled to the right diameter takes the same bulkhead fitting.
🧰 Step-by-step assembly
Mark the centre of the hole, drill at low speed, then deburr with sandpaper or a craft knife until the edge is smooth. Slide the body of the bulkhead fitting in from the inside, flange on the water side, with the flat gasket between the flange and the wall, then screw the nut on from the other side. Finally, glue the PVC pipe into the body with PVC cement, after degreasing both surfaces, and allow the cement its full drying time before filling.
Before commissioning, fill the tank above the bulkhead fitting and leave it for a day, with a piece of kitchen paper placed under the nut. A trace of moisture indicates a poorly seated seal: empty the tank to below the level of the hole, loosen the nut, re-centre the seal and tighten again by hand. If the paper stays dry, you can connect the rest of the circuit.
🌱 In aquaponics
Grow beds filled with clay pebbles are often drained through a bulkhead fitting at the bottom, topped with a bell siphon. The siphon empties the bed in one go as soon as the water reaches its top, and this ebb and flow brings air to the roots with every drain, since the water draining away lets air in between the pebbles. The guide to building your own aquaponic system recommends this type of bed for beginners.
For a grow bed of around a hundred litres sitting above the fish tank, a 32 mm bulkhead fitting in the bottom is enough, with a small pump that fills the bed. A cage or grid placed around the siphon stops the clay pebbles from blocking the pipe, while still leaving you access to the bulkhead fitting to check that it is watertight.
Technical specifications
Both sizes
- 32 mm
- 43 mm hole
- 40 mm
- 54 mm hole
- Connection
- PVC pipe for gluing
- Watertightness
- Flat seal under the collar
To budget for separately
- Drilling
- A hole saw of the right diameter
- Gluing
- PVC glue and pipe of the same diameter
In the box
- 1 bulkhead fitting with its locking nut and seal
Pipe and drilling diameters recorded on 11/10/2026 from the bulkhead fitting designation.
Which tank outlet fitting for your tank?
The same tank through-fitting in two sizes. What sets them apart is the tube and the flow rate to be handled.
32 or 40 mm?
One answer, and the table highlights the size that suits you.
| Tube (mm) | Hole to drill (mm) | Typical use | Price | |
|---|---|---|---|---|
| Recommended 32 mmYour choice | 32 mm | 43 mm | Small grow bed, moderate flow | $14.76 |
| 40 mmYour choice | 40 mm | 54 mm | Large tank, strong flow | $15.90 |
32 mmRecommended
What the size requires
Tube (mm)32 mm
Hole to drill (mm)43 mm
Typical useSmall grow bed, moderate flow
40 mm
What the size requires
Tube (mm)40 mm
Hole to drill (mm)54 mm
Typical useLarge tank, strong flow
Pipe and drilling diameters recorded on 11/10/2026 from the bulkhead fitting designation.
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Frequently asked questions
6 questions
6 key questions
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