Very cheap, and effective drop checker that I made for under $2.00
The design is based off the Red sea Co2 indicator "pictured below", which sells for $15.00 by me
Shopping list includes:
25cent egg with toy inside.
aquarium safe silicone sealant
First you will need to get yourself one of those 25cent eggs from those machines in the supermarket,the ones with the little toys in it. remove toy
Next you will need a funnel, lob off the top if its too large,The part with the spout is what you are going to use.
Finally, Silicone the parts together.
You can do one of two things here, you can leave the outer blue ring on the egg so it snaps off for an easy filling, or remove and seal it shut completely.
I find a rubberband useful for holding the suctioncup in place while the silicone is curing.
Water test in a glass
There you have it. An easy project for Measuring your Co2 levels.
This shouldn't take more than 10 minutes to make.
For under $2.00 you cant go wrong.