Most of you are pretty familiar with drop checkers and I have written about them on here before. If you're not (do a quick search on our blog), they're a must have product for a planted aquarium without any question of doubt. They measure your CO2 levels in your planted aquarium.
All drop checkers work in the same manner but all differ in looks and shape and the new Cal Aqua Nano Drop Checker has to be one of the smartest drop checkers I have ever seen. It's so delicately made and so tiny at a mere 3x3cm you could easily lose it in your planted aquarium. Whilst you don't of course want to lose it, keeping as much equipment out of the tank is the idea as it distracts from the aquascape. Any equipment in the tank should ideally be glass (where ever possible). This drop checker comes with everything you need too - 15ml of bromo blue which means that when your solution turns green, you have the ideal CO2 levels in your planted aquarium (30 ppm). It also comes with a clear suction cup.
Although aimed towards smaller aquariums I personally think it's suitable for all sizes of aquariums from the very small to the very large. Positioning wise, try placing it under your filter outlet - this will give you a really good idea as to your CO2 levels in your tank.
Are you using a Cal Aqua Nano Drop Checker in your tank? We would love to see a picture.