Aquarium CO₂ Drop Checker (monitors CO₂ levels)
Easy CO2 monitoring — tells you at a glance
- Regular price
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£11.99 - Regular price
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- Sale price
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£11.99
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Description
The Neutro Drop Checker is designed to indicate the amount of CO₂ in your planted aquarium. In order to understand the CO₂ level, a colour change occurs within the drop checker.
Drop checkers are the only way to monitor CO₂ levels on a daily basis with high accuracy. This drop checker requires Neutro Bromo Blue solution to work and needs to be purchased separately.
WIthout a drop checker you are guessing your CO₂ levels. This means plant growth will be sporadic and undesirable and this is why drop checkers play an important role when injecting CO2 into a planted aquarium. Drop checkers are very easy to use and start monitoring the levels immediately but always have a 2hour lag.
Directions to use:
- Turn drop checker upside down and fill drop checker bulb section 3/4 full of bromo blue solution (sold separately). Use a pipette if possible.
- Turn drop checker right way up (without spilling contents) and place inside aquarium so that it is visible. In terms of location, aim for 2-3" off the bottom.
- Within 2 hours drop checker will display a reading according to your CO₂ levels. Green is the ideal colour, yellow is too much CO₂ and blue is too little (adjust CO₂ output accordingly).
Key Point:
Remember your drop checker shows your CO₂ levels 2 hours in the past (essentially a delayed reading). Any changes you make need to be done slowly. In the morning you want your drop checker to be showing a green colour so it's quite normal to have CO2 coming on about 1 hour before the lights come on. If you are new to CO₂, then carefully monitor your fish in the morning to check they are OK. They should be fine but always check until you become familiar with CO₂ levels and how your livestock are.
Final thought. The big question you have to ask yourself if you don't know your CO₂ levels, how do you know if you have enough? 95% of all algae related problems are linked to insufficient CO₂.
Our Delivery Promise To You
We pack every order carefully at our UK facility and dispatch quickly, so your plants and aquarium products reach you in the best possible condition.
Order before 4pm Monday to Friday and we’ll dispatch the same day where possible. Most orders arrive within 1-2 working days.
If something goes wrong in transit, get in touch and we’ll help put it right.



Customers praised this CO₂ drop checker as "neat and unobtrusive" with "good quality" glass construction. It effectively monitors CO₂ levels with visible color changes. However, some noted it requires a pipette for filling and lacks instructions. A few mentioned the liquid can be difficult to read (blue vs green) and initial suction issues.
- Fantastic little gadget - takes all the guesswork out of CO2
- Lovely, neat little drop checker. Looks great in the tank (almost invisible in fact)
- A classy little piece of glass! Definitely not an eye-sore
- 5 stars: 25 (68%)
- 4 stars: 10 (27%)
- 3 stars: 2 (5%)
- 2 stars: 0 (0%)
- 1 star: 0 (0%)
If I'd needed instructions I would have bought the kit! This was to replace my previous one that mysteriously vanished after being cleaned...
Have only just put in the drop checker so far so good. The information was on the bottle so was easy to do.
Would be better if the product came with how to use instructions.
Seems to do the job. The liquid is very dark so it can be difficult to tell blue from green.
EXCELLENT
What can I say. It\'s a good quality drop checker
Neat, unobtrusive and works well.
Nice and small, great price and does the job.
nice and unobtrusive
fantastic little gadget - takes all the guesswork out of CO2
Nice drop checker. Looks good and does the job.
Great little drop checker. Not too conspicuous in the the aquarium, and the colour of the broom solution is clearly visible.
Nice quality, neat and unobtrusive for the aquarium. I have not set up my aquarium yet but love the look of the product and the service from AQUAessentials is second to none!
arrived promply lovely looking item I found it easy to fill with a small pipette very pleased with it
good quality but difficult to fill
This is a very simple, easy to use CO2 checker. As others have mentioned, you do need to use a pipette to get the solution in the reservoir.
Excellent quality product, easily visable, not too big and at a reasonable price.
Great little drop checker and great price. My only criticism is I wish the sucker would look clear when placed in the tank instead of looking white.
Lovely, neat little drop checker. Looks great in the tank (almost invisible in fact) and the price is excellent.
A classy little piece of glass! It looks great in the aquarium wherever you put it and is definitely not an eye-sore like some other drop checkers!
You can easily see any colour changes with the bromo blue solution which can also be bought off this site.
Does exactly what it was meant to do!
This is an excellent glass drop checker. I delayed ordering for a while as I was suspicious of the low price compared to other makes, I thought it may be very small or made of thin glass, but was pleasantly surprised as it's not.
I don't think it's that hard to fill as long as you are careful but a pipette or syringe makes it easy.
I use it in my large 135 gallon tank and it is easy to read but not over conspicuous.
As usual, very pleased with Aqua Essentials' products.
A great little product. Works well, looks good, although I did struggle to keep it stuck to the glass for a couple of days, I suspect that the suction pads needed to soften. Now it stays stuck all the time.
Great product but you must buy the pipette or it's hard to fill it up. Works a treat and the solution does change colour so be patient!
Very attractive piece of glass, there were some hair line imperfections around the neck of the drop checker but only when examines up close. Definitely deserves a place in your aquarium if your using pressurised Co2.
would have given more stars, same as the regulator i bought . no instructions ,on where the best place to put it in the tank. would have been better to know i needed a pippette when i ordered on the phone too. dont buy without . they cost 25 pence in shops . so it should really be part of the package
This is a great idea and the video on the Aqua essentials site was a lot of help.
I\'ve added the liquid and it hasn\'t changed colour at all. I mean I was hoping that the CO2 levels were correct...
The size of this product makes it very discrete in even a small aquarium, it is currently in use in a 1' cube. It is easy to view, making it a quick process to check on the colour of the solution inside, and the glass nature means it is very unintrusive to the look of the aquarium.
A pipette is highly recommended for inserting a 4dkH solution.
Very happy with the product, no downsides so far experienced
good product, looks good in my tank and does what its supposed too.
good quality for the price
I was using a DIY CO2 and until installing the drop checker and found I was not getting enough CO2 into my tank. Since then I have installed pressurised CO2 and my plants are growing rapidly. Great product.
Super piece of kit, so easy to set up and permanent check on my PH also looks good in tank
I have used pressurised CO2 for a number of years but it was only after talking witn Aqua Essentials that I realised that I had no idea whether I was putting enough gas into my 600 litre aquarium. Their suggestion that I should be using a drop checker (and they did not recoomend their own brand) to measure my CO2 input was,of course, exactly right and the one I have purchased does exactly what it is supposed to do.
Very nice looking drop checker. In use, I wasn't sure the 4dKH solution was actually green or if it were a reflection from the plants however once I got used to it and know how to inspect its absolutely fine, does the job well. Since then, I have piece of mind and also a healthy planted aquarium.

