# Other Aquarium Forums > Equipment and Accessories > DIY Projects >  DIY external co2 drop checker

## AQMS

This DIY external co2 drop checker is for eurpbrace tank or also known as perimeter bracing.
I start with used acrylic tube that i have leftover in my 'junk box' and some other connectors from
various filter spares and a white band sticker.

These are the spares that i used for this mini DIY project.



Acrylic tube.

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## AQMS

I bend the tube using a flame torch according to my tank perimeter bracing.



then paste the white sticker on the back of the tube where the 4DKH solution will be stored.

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## AQMS

Pictures without and with the white sticker.The sticker is to give a better visual reading of the checker.



And who can missed the devilish sticker....huha!ha!ha!

here is how the bottom part look like underwater.

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## wongce

hmm, good effort, but IMHO, i think it will work better is the tube is bigger in diameter... the air needs to contact with the solution to change colour.Thus more contact area= faster colour change....

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## AQMS

> hmm, good effort, but IMHO, i think it will work better is the tube is bigger in diameter... the air needs to contact with the solution to change colour.Thus more contact area= faster colour change....


yes very true but that is all i have left in the box. Guess, how many hours for the 4DKH solution to turn green??

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## wongce

> yes very true but that is all i have left in the box. Guess, how many hours for the 4DKH solution to turn green??


wah, hard to guess leh bro... 4 hours? lol just a lucky guess...

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## AQMS

> wah, hard to guess leh bro... 4 hours? lol just a lucky guess...


4 hours!! i wish.. :Roll Eyes:  12hrs  :Grin:  .... 
Because of the long neck and small diameter it took quite some time for the air to make contact with the solution.

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## wongce

Wah sai...12 hours ah.... haha

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## qngwn

Nice DIY, as usual! yes as what wongce mentioned, larger surface area for the solution to change colour. The diameter of the air column does not matter as much.. But with a bigger diameter tube, it gets harder to bend it.. :Opps:

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