Cal Aqua Labs Double Check v2

Cal Aqua Labs Double Check v2

  • Made of high-quality glass
  • Easy to read - 30 ppm CO2
  • Unique two-chamber system
  • Indicator and referencing solution included
  • Facilitates easy determination of the CO2 content
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Maintaining the appropriate CO2 level is critical in a planted aquarium. Too much CO2 may harm your fish, whereas too little CO2 decreases plant growth and allows algae to take over.

Cal Aqua Labs' Double Check series is the only all-glass dual-compartment CO2 checker that allows the user to accurately compare the CO2 level in your aquarium side-by-side against a standard reference. The top chamber holds the CO2 indicator solution, whereas the bottom chamber carries a CO2 reference solution. The reference solution color corresponds to 30 ppm of CO2 - a level that is widely accepted for good plant growth in most aquariums.

Each set includes a Double Check CO2 checker, 15ml Reference solution, 15ml Indicator solution, one suction cup and a reference chamber plug.


  • Handmade from the highest quality borosilicate glass imported from Europe
  • Unique dual-compartment design. Top compartment holds the Indicator solution, while the bottom compartment holds the Reference solution
  • No solution preparation needed. Required solutions are premade and included
  • Improved durability and ease of use
  • Easy to fill and remove solutions from both chambers
  • Simple to use, simple to read, higher accuracy than other single-compartment checkers


Cal Aqua Labs - Double Check v2
Height 54 mm
Width 40 mm
Width incl. suction cup 55 mm


  • Open the solution bottles by twisting the cap and cutting the tip with sharp scissors. Cut below the domed tip in order to expose the opening.
  • Fill the bottom chamber half way with the Reference solution
  • Fill the top chamber half way with Indicator solution. Tilting the device sideways and inserting bottle tip horizontally will make filling easier
  • Invert checker and attach suction cup. Install checker inside aquarium about 5 cm below water surface. Make sure that air is trapped inside separating the solutions from aquarium water. Tip: Wet glass stub before fitting suction cup
  • Compare the color of the Indicator solution with the Reference solution color. When the two colors are the same, optimum CO2 level (30 ppm) is attained

Cal Aqua Labs

Cal Aqua Labs

A stunning quality and innovative ideas around glassware articles for aquascapes have a name: Cal Aqua Labs. Lily pipes, permanent CO2 tests or inline diffusers are manufactured by highly experienced glass blowers. Their basic material is glass of the highest quality, whose clarity and stability is just stunning. The glassware is carefully manufactured by hand in keeping with very high quality standards. Every aquascape is embellished by these beautiful yet unobtrusive glassware products.

Those who do not want to compromise when it comes to glassware for aquascaping are exactly right to look at products by Cal Aqua Labs.

General information

Item no.
EAN 645080909784
Weight 0,50 kg
Shipping weight 0,50 kg

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This item has been rated 4.8 out of 5 stars
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