• Dymax Crystal CO2 Indicator, Large
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Dymax

Dymax Crystal CO2 Indicator, Large

Dymax Crystal CO2 Indicator, Large

$19.99
$19.99
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Shipping calculated at checkout.

Large Glass Drop Checker for Monitoring CO2 in Planted Aquariums

Dymax Crystal CO2 Indicator, Large, is a glass drop checker built to monitor CO2 levels in planted tanks. When paired with the Dymax CO2 Indicator Solution (sold separately), the solution inside changes color to indicate whether CO2 injection is excessive, optimal, or insufficient, providing a quick visual read without a separate meter or test kit.

At 2.5" x 1.2", the larger size gives a bigger color surface that's easier to read at a glance, especially useful in bigger tanks or busier aquascapes where a smaller indicator can be harder to spot.

Key Features:

  • Glass construction for a clear, accurate color read
  • Shows excessive, optimal, or insufficient CO2 at a glance
  • Larger 2.5" x 1.2" size for easier reading from a distance
  • Includes a suction cup for mounting inside the tank
  • Backed by a 1-year warranty from CoralVue and Dymax

Ideal For:

  • Larger planted tanks where a bigger indicator is easier to spot from across the room
  • Densely aquascaped tanks where a larger color surface stands out against plants and hardscape
  • Hobbyists running CO2 injection who want an ongoing visual check between water tests

Pro Tips:

  • Mount it at mid-to-low water level, not near the surface. CO2 tends to be less concentrated near the surface, so a mid-tank placement gives a more representative reading of what plants are actually receiving.
  • Give it time to stabilize after refilling. The indicator solution takes a while to fully react to a water change, so wait a few hours before judging the color against the reference chart.

Online exclusive: this item is ordered in for you and is usually ready within a few business days. Choose in-store pickup, local delivery or shipping at checkout.

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