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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

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Availability: In Stock.
Fulfilled by Amazon
Arrives Wednesday, May 20
Order within 13 hours and 50 minutes
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Features

  • Complete Kit: Our aquarium water C02 drop checker/monitor contains everything you need for efficient monitoring of CO2 levels in your tank. The fish tank C02 drop checker/monitor includes the highest quality glass drop checker, suction cup, and a 60ml bottle of 4dkh/pH reagent solution.
  • Easy To Use: The user-friendly CO2 detector is very convenient and gives you reliable reading in about 2 hours without syringes or other such items. Just fill the carbon dioxide monitor drop checker with the indicator solution and place it in the planted tank with the help of the suction cup.
  • Clear Readings: If the pH solution turns green/light green that means your aquarium tank has the optimal level of carbon dioxide. The yellow color of the aquarium kit liquid means the CO2 level in the water is very high while the blue color means there is insufficient level of CO2.
  • Essential Item: You need to be very careful about the health of your plants and carbon dioxide is one of their major requirements. This CO2 monitor kit is one of the most vital items of your aquarium kit that helps you to keep a constant check on CO2 levels in the water.
  • Quality Guaranteed: The high-quality glass CO2 checker. If you are not satisfied with the quality of the product or have some other issue, just let us know.

Brand: NilocG Aquatics


Liquid Volume: 60 Milliliters


Item Weight: 3.98 Ounces


Item Form: Liquid


Manufacturer: NilocG Aquatics


Is Discontinued By Manufacturer ‏ : ‎ No


Product Dimensions ‏ : ‎ 4.8 x 3.4 x 3.3 inches; 3.98 ounces


Item model number ‏ : ‎ 9902018


Date First Available ‏ : ‎ January 13, 2017


Manufacturer ‏ : ‎ NilocG Aquatics


Best Sellers Rank: #24,051 in Pet Supplies (See Top 100 in Pet Supplies) #34 in Aquarium Test Kits


#34 in Aquarium Test Kits:


Customer Reviews: 4.6 4.6 out of 5 stars (1,974)


Item Weight: 3.98 ounces


Manufacturer: NilocG Aquatics


Item model number: 9902018


Date First Available: January 13, 2017


Item Package Dimensions L x W x H: 4.7 x 3.4 x 2.3 inches


Item Dimensions LxWxH: 4.8 x 3.4 x 3.3 inches


Item Weight: 3.98 Ounces


Brand Name: NilocG Aquatics


Target Audience Keyword: Planted Aquariums, fish


Directions: 1. Fill the carbon dioxide monitor drop checker with the indicator solution. 2. Place it in the planted tank with the help of the suction cup. 3. Wait for about 2 hours for the pH solution to change color. 4. Compare the color of the solution with the color chart to determine the CO2 level in the water. 5. If the pH solution turns green/light green, the aquarium tank has the optimal level of carbon dioxide. 6. If the aquarium kit liquid turns yellow, the CO2 level in the water is very high. 7. If the solution turns blue, there is insufficient level of CO2.


Color: Transparent


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Wednesday, May 20

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Similar Products

Top Amazon Reviews

    • NilocG Drop Checker – Simple, Compact, and Does the Job. Does not replace Bubble counter.
Review Image by Ray C. Ray C.
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.. ... show more
Reviewed in the United States on June 8, 2025 by Ray C. Ray C.
    • It does take a few hours to change colors, water circulation is critically important
Came intact and works well. You need to give it a few hours to adjust
Reviewed in the United States on February 5, 2026 by Jennifer Whiteman
    • Glad it was just for me
Review Image by Morwynn Morwynn
Review Image by Morwynn Morwynn
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. ... show more
Reviewed in the United States on November 22, 2023 by Morwynn Morwynn
    • Doesn't take too much space and provides accurate readings
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. ... show more
Reviewed in the United States on July 17, 2024 by Hoonley
    • ❤️♥️
Great for planted aquarium health
Reviewed in the United States on January 5, 2026 by MC
    • It looks smaller than I thought.
Review Image by Anna Anna
Review Image by Anna Anna
Review Image by Anna Anna
Review Image by Anna Anna
Review Image by Anna Anna
A really well-designed drop checker, and it fits nicely in my 10-gallon tank. I was afraid it would be big and ugly, but it looks good, and I can always hide it somewhere in the tank. It comes with a solution (already premixed), so you don’t need to do anything—just put some drops in, and you’re good to go. The color changes are really noticeable; green and blue look truly different, so now my shrimp are safe ... show more
Reviewed in the United States on August 27, 2024 by Anna Anna
    • Easy to use
Review Image by ASLAN ASLAN
I hope it is accurate, i put around 20 drops in the checker and put it in the tank about 24 hours ago but still no color change, i had kept the previous checker from azoo in the tank just in case, it kept chamging its color according to the co2 injection but nilocg hadn't reacted so far. O might have put too mucb solution in the checker, internet says 15 drops but there was no onfo on the box, it just said "put the solution in the glass checker 1/3 - 2/3 full" and thats how much i filled it. Also, looking at the advertised solution and the one i recieved, i dont know if this is the correct one, adding a photo of the bottle hoping to receive clarification about it. ... show more
Reviewed in the United States on March 14, 2024 by ASLAN ASLAN
    • Fluid leaked out half the bottle
Review Image by Amazon customer Amazon customer
Review Image by Amazon customer Amazon customer
Review Image by Amazon customer Amazon customer
Glass came in fine and product worked for my CO2, however the liquid was at half when I opened the package and it looked to be spilled at some point. Liquid had spill marks but it was fairly dry so I don't think it was from this shipment.
Reviewed in the United States on December 3, 2023 by Amazon customer Amazon customer

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