NEW! "Double Check" CO2 Checker from CAL AQUA LABS

[Petrus]

I'm happy to announce CAL's version of CO2 Checkers - an 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. No more guessing which shades of green is considered "optimal". No more looking back-and-forth at color sheets to compare. You know the precise optimal CO2 level* is achieved when the colors in the two compartments are identical.

Click here for more information

* Reference solution is calibrated to 30 ppm CO2