NilocG Aquatics Glass CO2 Drop Checker – CO2 Monitor Kit for Aquarium Tank – Functional and Reliable – Transparent Drop Checker, 4dkh/pH Reagent Solution and Suction Cup

I’ve been using this drop checker in my planted tank for about two weeks now, and I don’t really have any complaints. It’s a small thing, but it does what it’s supposed to without getting in the way — which is more than I can say for a few other ones I’ve tried. First off, the design is clean and compact. It tucks neatly into the corner of the tank and doesn’t draw much attention, which I like. It comes with everything you need to get started, including the indicator solution and a pipette. The instructions were actually super clear — one of the few times I haven’t had to google a setup video just to make sure I was doing it right. I noticed the color change after a couple hours and it’s been easy to read since. The green shows up clearly through the glass and gives me a good sense of where my CO₂ is sitting throughout the day. So far, so good. That said, one thing to note — if you’re using a CO₂ system without a built-in drop counter, this won’t replace that. You’ll still need a separate bubble counter to dial in your injection rate. The drop checker tells you what’s going on in the tank, not what you’re actually dosing, so it’s more of a confirmation tool than a control one. What I Like: • Small and low-profile • Clear and simple setup • Comes with everything needed to start • Easy to read color change Heads Up: • Doesn’t function as a drop counter — you’ll still need one if you don’t already have it Overall, it’s a solid little tool for keeping an eye on CO₂ levels. It does the job without being bulky or confusing, and at this price point, I think it’s worth it. Would recommend if you want a reliable visual check without spending a ton..

.

My only gripe is that the accompanying CO2 detecting liquid could have been more

Works as it should. Came cracked at base, but still functions as it should. It's compact enough to be ALMOST unnoticeable. Price is on point. I have a cheap co2 system and it monitors levels as it should. Comes with the fluid and basic instructions. The suction cup hold good.

The drop checker was extremely easy to use, I just added the liquid inside flipped it over and pushed it into my tank. It took an hour or so for the color to change and stabilize itself to the CO2 in my tank. This is perfect for tanks that was to measure their CO2 to make sure their plants are provided with the nutrition they need to grow. Not only that but it helps you control the algae growth in the tank by knowing how much CO2 is in there. One thing to note is that if you have a tank smaller than 3 gallons, it will a lot of the space. I currently have this in my 2 gallon tank and it is very obvious and cannot be hidden as well, but considering the pros it brings this is nothing.