32 mm black rubber push-fit seal by Growrilla, manufacturer's marking on the front face

Growrilla 50 mm black rubber push-fit joint, front view showing the sealing groove

63 mm black rubber push-fit seal by Growrilla, shown at three-quarter view with its double lip

Push-fit fittings for RDWC tank, 32, 50 or 63 mm

Name: Push-fit fittings for RDWC tank, 32, 50 or 63 mm
Brand: Growrilla
SKU: GROW-PACK-GSKGGDN32-10
Price: 20.9 EUR
Availability: InStock

20,90 €

These push-fit rubber seals make the tube passage through the tank wall watertight in an RDWC circuit. They are available in 32 mm for a 2.0 circuit, in 50 mm for a PRO circuit and in 63 mm for a build-your-own installation, in packs of 10, 25 or 50.

Ref. GROW-PACK-GSKGGDN32-10·Hydroponic spare part

Diameter : 32 mm ×10

32 mm ×10

50 mm ×10

63 mm ×10

32 mm ×25

32 mm ×50

50 mm ×25

50 mm ×50

63 mm ×25

63 mm ×50

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The summary

What it is: the flexible seal that makes the tube passage through the tank wall watertight.
The right diameter: 32 mm for an RDWC 2.0 circuit, 50 mm for a PRO circuit, 63 mm for a bespoke installation.
When to order: at the first sign of weeping, and before any circuit dismantling.
How many you need: two per grow tank, plus two for the controller pot.

Replacement seals for push-fit fittings, in 32, 50 or 63 mm

Push-fit seals for RDWC tanks are rubber rings that make the point where the pipe passes through the tank wall watertight, without glue or tools. The diameter is that of the pipe: 32 mm for an RDWC 2.0 system, 50 mm for a PRO system, 63 mm for a made-to-measure installation.

The watertight integrity of an RDWC circuit depends on its push-fit seals. The seal is the rubber ring housed in the bore of a tank, which the connecting pipe passes through and compresses. As long as it retains its elasticity, the solution stays in the tank; once it loses it, a ring of moisture appears first beneath the fitting, then a puddle.

The seal is neither tightened nor glued: watertightness comes from the pressure of the tube on the rubber, and nothing else. That is why a worn seal cannot be saved by forcing the tube in further, and why it should be replaced rather than refitted. The same principle means you can dismantle an entire network by hand and reconfigure it between two cycles, without tools or glue.

⚫ Three tube diameters

The seal size is that of the pipe, never that of the hole drilled in the tank, and this is the mix-up that would lead you to order the wrong item. The 32 mm seal fits a 38 mm hole, the size used on a RDWC 2.0 tank. The 50 mm seal fits a 58 mm hole, the size used on a RDWC PRO tank. The 63 mm seal needs a 70 mm hole and matches neither kit: it is meant for set-ups built up piece by piece.

A clean bore and a properly rounded seal

A grommet only holds in a hole of the right diameter, free of swarf and with smooth edges. Once pressed into the drilled hole, it must sit snugly against the edge all the way round and take a perfectly circular shape: a twisted or half-extruded grommet lets water through as soon as the system is pressurised. Smooth the end of the tube as well, because a sharp edge will cut the lip of the grommet as you push it in.

Replace the airstones at the same time as the seals

Redoing the seals means lowering the water level and opening the circuit, which gives access to the bottom of each tank. This is the time to replace the cylindrical air stones, which clog up over successive cycles and then produce large, irregular bubbles. You thus put the network back into service with fresh sealing and oxygenation, in a single intervention.

🔍 Identifying a worn seal

A seal does not give way all at once: it gradually loses the elasticity that holds it against the pipe, after repeated dismantling and seasons spent compressed, and then it starts to weep. The fault can be spotted well before any puddle appears, provided you look at the base of each fitting whenever you check the control pot. Four situations should make you think of a replacement, and each can be checked in a few seconds, tank by tank.

A wet patch beneath a fitting

Even a very slight one indicates a seal that has lost its grip on the tube.

A washer left compressed

After a season under a pipe, it does not always return to its original shape when reassembled.

A redrilled hole

A new hole deserves a new gasket, fitted to a deburred edge.

A twisted seal

A seal that has not formed a true round shape will let water through.

🔧 Installation and quantities

Push the seal into the hole until its groove fits snugly around the edge of the wall. Lubricate the inside of the ring with a little liquid soap, which helps the pipe slide in. Then insert the pipe, pushing and twisting in the same movement, until it sits firmly with no play. The operation takes a little force and patience the first time, then becomes quick.

The pack contains seals that are all identical, in the diameter you choose, in packs of 10, 25 or 50. Each growing tank has two seals, one per connecting tube, and the controller pot has two more: a system with 8 growing pots therefore uses 18. The pack of 10 is enough for a partial overhaul, the pack of 25 for a complete overhaul with some to spare. Store the rest in its sealed bag, lying flat and away from light and heat, so that the seals are still supple at the next dismantling.

🐟 Outside the kit, in aquaponics

These seals are not only for 19 L tanks. They connect any rigid plastic container to a 32, 50 or 63 mm pipe, which makes them a common part for connecting a grow bed to a fish pond, a settling tank to a biological filter, or a buffer tank to the rest of an aquaponic installation. You drill the wall to the stated diameter, deburr it, then fit the seal as you would on a tank from the kit. On a large container, the 63 mm lets through a greater flow than a 50 mm pipe, which matters for a gravity return to the pond.

Technical specifications

The essentials

Material: Flexible rubber
Tube diameters: 32, 50 or 63 mmThis is the measurement of the tube that passes through, not the hole itself.
Quantities: 10, 25 or 50 pieces
Assembly: No glue or tools requiredA little washing-up liquid makes inserting the tube easier.

Drillings and origin

32 mm seal: Bore of 38 mmTanks for RDWC 2.0 kits.
50 mm seal: Bore of 58 mmTanks for RDWC PRO kits.
63 mm seal: Bore of 70 mmSystems built up component by component.
Origin: Italy

In the box

10, 25 or 50 push-fit seals, all at the same diameter, depending on the pack selected.

Pipe diameters, drillings and installation advice taken from the product pages and the manufacturer's RDWC 2.0 manual, on 07/10/2026.

Manufacturer and product safety

Manufacturer: Growrilla di Milone Giulio
Postal address: Via Fiano 207, 10070 Robassomero (TO), Italie
Contact: info@growrillahydroponics.com
Website: growrillahydroponics.com

Information provided under Regulation (EU) 2023/988 on general product safety.

Estimate your
delivery time

The seals are sent in a bag from the workshop in Robassomero, near Turin. The exact charges and final delivery times are shown at the basket once the address has been entered. Outside the European Union, import duties and taxes are payable by the recipient.

Frequently asked questions

8 questions

6 key questions, 8 in the detailed view

How do you know which diameter to order?

How many seals do I need for my setup?

Can a single seal be replaced?

Should you drain down before the job?

Does the 63 mm seal fit a kit from the catalogue?

What should you use to lubricate a seal?

Does the 32 mm seal accept a 1-inch pipe?

Does it fit in any tank?

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Push-fit fittings for RDWC tank, 32, 50 or 63 mm

The summary