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..

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.

I’m glad I purchased this for myself as the one I received wasn’t in the best of shape. The outer box had gotten wet at some point (this was the only item in my shipment that had any sort of damage), the inner box holding the glass drip checker was completely open, and I’m not sure if it was supposed to come with a reference card or instructions as seen online or not, but I didn’t have one. There is a chart and some limited instructions printed on the drop checker box that I didn’t notice at first and very nearly threw away. I had to look online for information about where in the tank to place the checker, how often to change the fluid, etc. Other than that, seems to be of good quality and should work just fine.

Beautiful and elegant. Easy to clean.

Update: 2022-12-14: I got two replacement suction cups - This means I don't have to toss the drop checker. It's back in the tank and working perfectly. FYI, trying to use heat with the old suction cup doesn't work. Just ask for a replacement. Their customer service is great! Update: 2022-12-08: I wrote support and they are sending me a replacement suction cup! If you need a replacement, reach out to them. I think it's a good piece of glass - and works... I mean it's just glass, so why wouldn't it. Three years later the suction cup is hard as a brick and useless and it won't adhere to the side of the tank. Using a little silicone lubricant doesn't help even if the glass has been cleaned. Ideally, we'd be able to buy suction cups to keep using this vs making it a disposable object that adds to the planet's trash and makes us spend more.

Came intact and works well. You need to give it a few hours to adjust

It looks great Glass came full intact But I'm not too sure on the liquid I had it in my tank for 24 hours and it just stays blue .. so I'm not too sure what's up

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