Solution checker aquarium

If you want to know whether your plants carry out the photosynthesis adequately, a great idea is to monitor the concentration of carbon dioxide. It helps also to check if your fish lack oxygen. In this article, you are going to find out what is a CO2 drop checker solution, how to use it properly and what outcomes you can expect after installing CO2 drop checker inside your aquarium.


What is a drop checker?

In simple words, the drop checker is a pH reagent. If we fill this product with drop checker solution and install it inside the aquarium, it is going to show us in colors the pH of our aquarium water. It works like a regular pH test kit which many fish keepers already have but with one difference. It measures the CO2 content of the aquarium water all the time. It is not like the pH test strip that we put into the water once, get the result and we may throw this out. In case of the drop checker, it happens constantly. And especially if you inject CO2 into your aquarium water it is good to know if we carbonated our aquarium water high enough to right balance plants growth but low enough to avoid poisoning your fauna.

Drop checker solution consists of a pre-made 4dKH solution containing the appropriate amount of indicator. Check products on our site and rely on trustworthy brands. It is easy to use, no mixing required. When it comes to other brands, you sometimes have to mix it with water or other liquids. Our drop checker solution is complete and ready to use.

an aquarium

How to mount the drop checker kit?

  1. Open the drop checker solution bottle by twisting the cap and attach suction cup

  2. Turn the drop checker upwards.

  3. Simply fill the drop checker halfway.

  4. Slowly rotate the drop checker so that the indicator solution enters the chamber and the air is trapped in the vessel.

  5. Install the drop checker with the indicator solution inside your aquarium. Make sure to put it 1-2 inches below the water surface and try to avoid places that are close to the carbon dioxide diffuser so that the CO2 bubbles won't derange the readings.

  6. Remember about the replacement of the indicator solution once every two or three weeks, otherwise the readings may become inaccurate. Clean the drop checker with tap water. Nothing should remain in the chamber, dry it and start the process once from the first point.

Visit our site and check our videos on how to fill the drop checker.

How does it work?

When the CO2 drop checker is completely submerged in the tank, the carbon dioxide will flow from the water into the drop checker and will be absorbed by the indicator solution. Depending on the concentration of CO2, the indicator solution will change its color. Wait at least 12 hours before changing anything. After this time the readings will be accurate.

  • If the indicator solution turns blue the tank water is alkaline (above pH 7) and it means that you can increase the CO2 injection.

  • If the indicator solution turns green or lime-green the water is neutral (equal or almost equal pH 7) and it means that the CO2 dosing is correct.

  • If the indicator solution turns yellow the water is acidic (below pH 7) it means that you should reduce your CO2 dosing.

drop checker solution colors

There is no doubt that CO2 regulator kit with drop checker is designed specially for a planted tank but if you are able to keep stable parameters, fish won't care about it. Moreover, if the vegetation is dense, it will be really rewarding environment for some kinds of species. They will have more places to hide and rest. Most agree that 30 ppm (particles per millions) of CO2 in our tank is beneficial for our live plants and not toxic to the fauna.

To control the concentration of CO2 in our tank the second device is useful- a bubble counter. It allows to estimate of the CO2 injection rate by counting how many bubble pass through the device per minute. If the bubble counter is combined with the drop checker, it gives us pretty faithful readings.

There are no two tank setups that are exactly the same. As a result, it is impossible to suggest with any accuracy how much should the bubble rate be set. It is better to start from the lowest rate and add a little bit more over time than inject too much and watch our livestock dying. It is recommended to experiment with CO2 levels before introducing fish to the aquarium.

As it was said, it is hard to estimate the amount of bubbles but if simple orientation is needed then the list below should be helpful:

  • 40-60 gallon aquarium- 60 bubbles per minute

  • 20-40 gallon aquarium- 30 bubbles per minute

  • 10-20 gallon aquarium- 12 bubbles per minute

a planted tank


CO2 is one of the most important elements in the planted aquarium. You can grow your aquatic plants in your aquarium 5-10 times faster if you supplement them with CO2. But just like with everything, you need to be moderate. If not, too much of CO2 can cause some irreversible changes and the drop checker solution turns out to be a great method to control aquarium parameters.

a drop checker with solution

Check products on our site and rely on trustworthy brands. You can also purchase complete CO2 regulator kits with the bubble counter. We have free shipping for orders over 70$.

Pick your item, and we are going to deliver it for you as fast as it is possible. Remember about our special discounted price with the code after you sign up on our site.

CO2 regulator kit