Drop checker kit

With the “Drop” CO2 tester kit you have everything to measure the CO2 value of your tank. Just look at the color: Is it light green? Then your CO2 is fine! This CO2 tester kit is ideal because:

  • Everything in 1 kit to start measuring right away
  • Looks very stylish in your tank & almost invisible
  • Very sturdy laboratory glass: does not break easily
  • Easy & quick to clean
  • Very easy CO2 measurement: healthier aquarium plants

Do you dream of a beautiful, green planted tank? Then you need to provide good CO2. This kit will help you do just that.

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Everything in 1 kit

Made of strong glass

Gemakkelijke setup

Easy to measure CO2

CO2 for a healthy planted tank

Do you have a planted tank and you use strong aquarium lighting? Then it is important that you add enough CO2 to your tank. Because without CO2, your plants will grow poorly, they will start to detoriate and then: algae!

Measure your CO2 properly and you can create the tank of your dreams.

hoe werkt PlantedBox

Measuring CO2 becomes a breeze

But how do you know if you have enough CO2 in your tank?

Well, this drop checker kit makes it very easy to measure the CO2 in your tank. You hold the checker upside down, with the open neck facing up. You then add the blue drop checker mix via the handy dispensing bottle, and then you carefully turn your drop checker over and place it in your aquarium.

After a few hours, the liquid will change in color. Does it remain blue? Then you have a CO2 deficiency. Is it yellow? Then you have too much CO2. Is it green? Fine, then you’re about right (+- 30ppm).

Easy, right? 🙂

Free advice tailored to your aquarium

Are you having problems with your tank? Are you struggling with algae and want some advice? Download my ebooks or read the tips on my blog.


What is included in this drop checker kit?

This drop checker kit includes:

  • 1x “drop checker”
  • 100ml drop checker mix

100ml of drop checker mix will last about 33 weeks if you change weekly. Nice and long.

How do you place the drop checker in your aquarium?

1. Turn the drop checker upside down
2. Add the blue drop checker mix until halfway down the drop checker
3. Now carefully turn your CO2 continuous test over & place it in your tank

When do you know you have enough CO2?

It’s very simple. Just look at the color of the solution:

  • Blue: not enough CO2. Carefully (!) inject some more CO2 into your tank.
  • Green: OK, but a little more would be better
  • Lime green: OK
  • Yellow: too much! Add less CO2 or put more oxygen into the tank

That’s it!

How to clean?

Replace the solution at every water change. Just turn the drop checker over & rinse it out with RO water  (not tap water, as it may affect the result). If necessary remove algae & clean the suction cup with some filter wool so it adheres well again.

Is the drop checker indicator mix toxic?

A few drops are not dangerous to your fish & shrimp, but avoid situations where you accidentally drop the whole bottle in your aquarium. Also – like with all other products – keep out of reach of children.

Should I flush the drop checker?

It is best to use RO water so there is no lime residue left behind that may affect the results.


Customer Reviews

Based on 173 reviews
Joseph Peters
Heel goed product

Nu een gemak om de CO2 te controleren .

Werkt prima

De co2 tester werkt prima, ook de levering was sneller als verwacht, op de website staat tot 3 dagen maar de volgende dag was het pakketje al binnen.
Overigens heb ik ook veel geleerd van de blogs op de website, top

Pim Hup
Goede kwaliteit en service

Goede producten en service!

Goed product en veel vloeistof voor weinig geld

Werkt goed fijne co2 checker

Top product!

Alles zeer goed ontvangen. Co2 tester kit werkt super. Absolute aanrader!