Ailindany CO2 Drop Checker Glass Aquarium Monitor CO2 Indicator for Planted Fish Tank (Transparent, Drop Type)

Got this one after the one we had that suctioned under the water broke when trying to clean. No longer have to deal with a suction cup. Just sits right on the rim of the tank. Works well. Can easily slide along the rim, so if you have a lid or have small kids that might reach up and grab it, might not be for you.

It works. Kind of big. Not the same size and quality of the UNS version.

The design is much better looking than the suction cup ones that go inside the tank. I've had it on my tank for 2 days now and it has the same color compared to the one I've been using as pictured. Although, the glass is a little disfigured, no big deal. Does what it's supposed to! I'll probably replace all of my drop checkers with these.

I agree with another reviewer, the solution is spread thinner so it's a bit harder to discern the color than the suction cup kind (that contains more solution)Also - and this could be my hard water - but since the opening to the water is much smaller, I've had a surface tension bubble form at the bottom of the drop checker that prevented the exchange needed for the color to change. I pulled the checker out and popped the bubble and it seemed to pick it back up afterwards.All in all, I think I'm going to go back to the suction cup drop checker because it was easier to read.

I ordered this drop checker because I liked that it was very minimally inside the tank.. However it was very inaccurate for me. I struggled with dialing in my Co2 because it seemed like the solution would never change color. I decided to put a second drop checker of a different style inside the tank along with this one (and used the exact same bottle of solution). Sure enough the new one would change color and this one would not. I don't know if it's the shape that is causing the inaccuracy... but I am not using it. I have resorted to a different style drop checker and will be throwing this one away.. You can see in the picture provided the 2 drop checkers that have the same solution and were put into the tank at the same time and the extreme difference in color.

Seems to work well. Perfect size for my nano tank. The color can be difficult to read at times, but it's a great indicator for general ph levels.

AWESOME HANGOVER THE EDGE DESIGN! HIGHLY RECOMMEND.

I like how i can just hang this on the rim of the aquarium with no need for any suction cup. It's less conspicuous and helps keep equipment out of the tank for a clean look. Ordered this one for a several bucks more, since the cheaper one I ordered (from a different vendor) still hadn't arrived after two months, even though it 'shipped'.