Glass CO2 Check Valve

£4.49
 

Key Facts

  • Prevents water back-flow / siphon.
  • For 4mm internal diameter tubing.
  • Made of crystal clear glass.
  • Easy to installation.
  • Attractive design.
  • Comes with 2 x suction clips

Description

Without a check valve in place, when the flow of CO2 is turned off (e.g. overnight when it's not needed) water can siphon down the tubing from your aquarium and enter your solenoid, causing it to flood, which may damage it, or require maintenance to dry out the water.  This simple item eliminates that possibility by not allowing air or water to flow in the opposite direction to which it is installed.

Instructions

  • Because the item is made from glass it is inherently delicate, and extra care needs to be taken when attaching the tubing. It is highly recommended that the tubing is first warmed in freshly boiled water to soften the tip when pushing onto the diffuser inlet.
  • This unit uses gravity to operate, it must therefore be aligned in an upright/vertical position - as shown in the picture.
  • Looking at the valve, you will notice that one end is slightly more tapered (narrower) than the other. It may also have a faint line running about around the tapered section - this is the inlet and should be at the bottom. To verify; while holding the valve in a vertical position, you should not be able to blow down the outlet. If you can, you've got it the wrong way around.
  • Push CO2 tubing onto corresponding inlet/outlet as far as you can.
  • Tip: Softening the tubing in freshly boiled water will make it easier to push the tubing onto the valve.
  • Click here to read the full check valve setup guide

Customer Reviews

Average Rating
4.5
  • A
    Andrew C.
    5
    4th Jul 2026
    Works exactly as it should Works exactly as it should
  • G
    Greta P.
    5
    22nd Jun 2026
    Stronger and sturdier than I expected and looks great Stronger and sturdier than I expected and looks great
  • D
    Darren L.
    5
    6th Mar 2026
    Beautiful check valve. Works well and requires less pressure to ‘crack’ Beautiful check valve. Works well and requires less pressure to ‘crack’
  • S
    Steven C.
    5
    22nd Jan 2026
    Works as intended! Works as intended!
  • J
    Joanna N.
    5
    17th Dec 2025
    Looks nice and it works! Looks nice and it works!
  • C
    Colin E.
    5
    3rd Sep 2025
    Unobtrusive and easily fitted. Unobtrusive and easily fitted.
  • C
    Cjohn C.
    5
    4th Aug 2025
    Easy to install and looks nice too Easy to install and looks nice too
  • M
    Mauro C.
    5
    6th Jun 2025
    Sleek design, works perfectly, and keeps water out Sleek design, works perfectly, and keeps water out
  • T
    Terence B.
    5
    16th Jan 2025
    Super sleek, functional, and arrived quickly. Super sleek, functional, and arrived quickly.
  • G
    Golan L.
    5
    22nd May 2023
    The best check valve I ever used ( and try almost everything) Thank you co2 supermarket for great service and super quality product that rise above all !!! The best check valve I ever used ( and try almost everything) Thank you co2 supermarket for great service and super quality product that rise above all !!!
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