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Flexible or rigid PVC pipe: a coil, socket, or skip

Updated: October 2026

The pond cabinet needs a line you can see through, or a straight socket that will not kink, and both are sold as PVC. Flexible or rigid PVC pipe is that choice. Clear tube bends onto a barb. Rigid PVC keeps a solvent-weld joint. Prices are on the [PVC pipe comparison](/hub/rods-and-pipes/pvc-pipe). A qualifying purchase can earn a commission at no extra cost to you. If the run bends onto a barb, buy the clear coil whose bore and length match. If the fitting is a rigid socket of about 25 mm outside, the black 1 m pipe is the rigid row here. The earlier fork is the [PVC pipe buying guide](/hub/rods-and-pipes/pvc-pipe/sub/pvc-pipe-buying-guide).

The pond cabinet needs a line you can see through, or a straight socket that will not kink, and both are sold as PVC. Flexible or rigid PVC pipe is that choice. Clear tube bends onto a barb.

Our top picks

Kesote Kesote 7 by 9 mm tube

Best overall

Kesote Kesote 7 by 9 mm tube
8.8/10about £4.99
View offer
eco-filtration eco-filtration 25 mm waste pipe

Rank 2

eco-filtration eco-filtration 25 mm waste pipe
8.4/10about £10.20
View offer
Dcizlont Dcizlont 8 by 11 mm tube

Alternative

Dcizlont Dcizlont 8 by 11 mm tube
7.8/10about £11.69
View offer
On this page
  1. 1.Two PVCs, two labels
  2. 2.When the clear coil is the one to buy
  3. 3.When the rigid pipe is the one to buy
  4. 4.The line you must not cross

Two PVCs, two labels

RS describes the catalogue split: PVC-U is rigid and unplasticised, and plasticised PVC is the flexible tube. None of these listings prints BS EN ISO 1452. Clear tube here is inside by outside. Kesote is 7 mm by 9 mm, so the bore is 7 mm. TA-VIGOR is 9 mm by 12 mm, and Dcizlont is 8 mm by 11 mm. eco-filtration states 25 mm outside and a wall of about 2.5 mm, not a 25 mm bore. Order 9 mm as an outside diameter and the 9 mm by 12 mm coil will not enter a solvent socket.

When the clear coil is the one to buy

Buy the coil when you want to see the flow and the fitting is a barb. Kesote is £4.99 for 3 m of 7 mm by 9 mm tube, 4.4 from 4,658 reviews. Buyers run a small pump or a siphon, and the same reviews say it kinks. It states no pressure. It is the best value here for a short low-pressure line, and the wrong buy when the pump needs a stated pressure. TA-VIGOR is 2 m of 9 mm by 12 mm tube at £8.89, stating -5 °C to 60 °C and 0.2 MPa. Dcizlont is 10 m of 8 mm by 11 mm tube at £11.69, stating 5 bar. Do not copy another maker's temperature onto these coils.
Kesote Kesote 7 by 9 mm tube

Testsieger

Kesote Kesote 7 by 9 mm tube
8.8/10about £4.99
View offer

When the rigid pipe is the one to buy

Buy rigid pipe when the fitting is a socket, not a hose tail. The rigid pond or filter line here is eco-filtration: black, 25 mm outside, wall about 2.5 mm, 1 m, £10.20, with reviews that say the joints fit. It is the top pick when the socket is about 25 mm solvent-weld, and the wrong pipe for a 40 mm bath waste, which is a larger nominal size on solvent weld waste pipe. Do not cement a 7 mm coil into that 25 mm socket. Kair and Fantronix are 100 mm inside, 350 mm, with a 1 mm wall. They are fan sleeves, not a pond line. BroLuka's title says 16 mm by 20 mm, while the components line says latex tubing. It is not the rigid choice.

The line you must not cross

Do not solvent-weld the clear tube. Flexible vinyl is not rigid PVC, and cement will not make a reliable joint to a waste socket. The barb and a clamp behind the last barb are the joint, and the steps are on how to join PVC pipe. Do not treat food-grade, FDA, RoHS, or REACH as permission to plumb UK drinking water. If the pump needs a stated pressure and a long visible run, Dcizlont is the coil that prints 5 bar. If the run is a straight 25 mm socket, eco-filtration is the rigid row.

Common questions

Should a pond filter use the clear coil or the black rigid pipe?
Use the clear coil if the filter tail is a barb, you want to see the flow, and the bore matches 7 mm, 8 mm, or 9 mm. Use the black eco-filtration pipe if the fitting is a rigid socket of about 25 mm outside and the run is within 1 m. Do not cement the coil into that socket. If the pond plumbing is actually 32 mm or 40 mm waste, neither of these rows is that nominal size.
What does 7 by 9 mm mean?
On Kesote it means 7 mm inside and 9 mm outside, in a 3 m coil at £4.99. The first number is the bore that has to match the barb. It is not a 9 mm solvent-weld outside diameter, and it is not a 25 mm pipe. TA-VIGOR’s 9 by 12 mm and Dcizlont’s 8 by 11 mm use the same inside-by-outside labelling.
Which coil states a pressure?
Kesote states none. TA-VIGOR states 0.2 MPa, with -5 °C to 60 °C, on a 2 m tube at £8.89, from eight reviews. Dcizlont states 5 bar on a 10 m tube at £11.69. Those figures are the listings’ claims. This comparison did not pressure-test them. If the pump needs a stated pressure, Kesote is the one to skip.
Can I solvent-weld the clear tube to a rigid fitting?
No. The clear coils are plasticised tube for a barb and a clamp. Solvent cement is for rigid PVC of one system, such as the 25 mm eco-filtration pipe into a matching socket. Cement on vinyl does not turn a 7 mm bore into a 25 mm joint. If the fitting is rigid, buy the rigid pipe that matches it.
Is food-grade clear tube safe on drinking water?
Not on the strength of food-grade, FDA, RoHS, or REACH. Wholesome fittings come under the Water Supply (Water Fittings) Regulations 1999, and a WRAS approval is for one product and it expires. None of these coils prints a WRAS number. A clear wall lets you see the flow. It does not make the tube lawful on UK drinking water.
When is the 100 mm duct the wrong rigid PVC?
When the question is a pond, an aquarium, or a small filter line. Kair and Fantronix are 100 mm inside, 350 mm long, with a 1 mm wall and female ends for a fan spigot. They are ventilation duct, not a 25 mm solvent-weld pipe. A 350 mm sleeve does not answer a hose-tail fitting, and you should not bury that 1 mm wall.

Related pages

Best PVC pipe

PVC pipe

PVC pipe buying guide: name the job before the price

How to join PVC pipe: waste, a duct, or clear tube

Solvent weld waste pipe sizes: 25 mm against 32 mm

Sources

Public UK sources and the amazon.co.uk extracts used for this comparison. Retrieved 16 October 2026.

  1. Water Supply (Water Fittings) Regulations 1999 (retrieved 16 October 2026)
  2. Approved Document H: drainage and waste disposal (retrieved 16 October 2026)
  3. Approved Document F: ventilation (retrieved 16 October 2026)
  4. BS EN ISO 1452-2:2009, BSI summary (retrieved 16 October 2026)
  5. WRAS approvals directory, PVC section (retrieved 16 October 2026)
  6. Brett Martin waste FAQ (retrieved 16 October 2026)
  7. HSE CIS27: solvent ventilation (retrieved 16 October 2026)
  8. amazon.co.uk listings for the nine ASINs in this comparison (retrieved 16 October 2026)