Fluval CO2 Aquarium Indicator Kit

Skip image gallery
Slide 1 of 6
$16.99 Chewy Price
Promo, New Customers Only: Spend $49+, Get $20 eGift Card + Free Shipping with code: WELCOME
In Stock
FREE 1-3 day delivery on first-time orders over $35
Free 365-day returns

Pay in 4 interest-free payments on purchases of $30-$1,500. .

About This Item

Details

  • Helps you measure and gauge CO2 levels in your aquarium.
  • Comes with everything you need for proper CO2 monitoring, including one CO2 indicator, a 10ml CO2 indicator solution and a color sticker to reference CO2 levels.
  • Can be used in both saltwater and freshwater aquariums.
  • Helps you maintain CO2 levels in your aquarium to encourage proper plant growth, development and survival.
  • Promotes a vibrant, healthy planted aquarium for any-level aquarist.

Questions & Answers

2 Customer Questions

Will the CO2 indicator solution need to be replaced?

Answer by Chewy • Jan 14, 2019
This kit includes one 10 ml CO2 indicator liquid. The liquid will need to be replaced at some point, depending on usage.

how do you use this--do you mix the solution with the aquarium water?

Answer by Chewy • Jan 25, 2019
CO2 Indicator Kit, Directions for Use: 1. Detach the reservoir from the cap of the CO2 Indicator. 2. Add 1 mL (0.03 fl oz) of the Indicator Liquid to the reservoir of the CO2 Indicator (fill to clear line) and reattach both parts of the CO2 Indicator. Do not add water. 3. Place CO2 Indicator vertically inside the tank (cone facing up) and attach to the wall of the tank using the suction cup. 4. Place the color check sticker over the suction cup on the outside wall of the tank.
Reviews
Write a Review
2.2
Rated 2.2 out of 5 stars
6 Ratings
Terms & Conditions

5 Customer Reviews

Rated 2 out of 5 stars
By Colby on Dec 12, 2025

Expired solution

I wouldn’t say this is a bad review but the CO2 solution in the box was expired by more than a year. Chewy did refund the order. I do like the design though and

I wouldn’t say this is a bad review but the CO2 solution in the box was expired by more than a year. Chewy did refund the order. I do like the design though and it’s easy to add the CO2 solution to this CO2 checker.

Rated 3 out of 5 stars
By Edward on Sep 13, 2025

Was easy to install

Not a great product i mean half the time your not sure of the color and then what ?

Not a great product i mean half the time your not sure of the color and then what ?

Rated 1 out of 5 stars
By Kimberly on Feb 26, 2025

no luck

I didn't have luck with this. Not sure it really works. I followed instructions, but the liquid remained blue even after more than a week of adding liquid co2

I didn't have luck with this. Not sure it really works. I followed instructions, but the liquid remained blue even after more than a week of adding liquid co2. the liquid also seemed to go down everyday. not sure if it's leaking into the tank...? i wouldn't recommend because there is no way to know if it's actually working

Rated 1 out of 5 stars
By lisa on Mar 17, 2025

Wrong tube

This is not a chewy issue. The product does not supply the correct tubing needed for CO2 gas. The tubing provided explodes.

This is not a chewy issue. The product does not supply the correct tubing needed for CO2 gas. The tubing provided explodes.

Rated 5 out of 5 stars
By Justin on Jan 20, 2023

Super easy to use CO2 test

Considering dabbling with supplemental CO2 in my tanks and this was a great first step to understanding what levels are already present.

Considering dabbling with supplemental CO2 in my tanks and this was a great first step to understanding what levels are already present.