# Other Aquarium Forums > Equipment and Accessories > DIY Projects >  DIY CO2 bubble counter and checkvalve

## dc88

This is an excellant idea originally from APC posted by John N :
http://www.aquaticplantcentral.com/f...s-recipes.html

Adopted here with slight modification and using parts from local sources : 

(1) Get a 5ml syringe from Guardian Pharmacy (cost S$0.30) and a typical checkvalce from LFS (~$2) :



(2) Use a pen knife to cut the rim off the syringe tube (do it with care) :



(3) Fill the syringe tube with water to half the level, and plug in the check valve. 



(4) Connect the assembly. (CO2 bottle->this bubble-counter/check valve assembly -> diffuser (or reactor) at the tank.



Compare this ~$2.3 gadget with a commercial bubble counter (~S$5) and a check valve (~$2) - total S$7.
this is perfect for small size tank with DOY CO2 system !

(Disclamer : have not tested with pressurized CO2 system yet.)

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## BFG

What an eye-opener! I have 2 of these parts together and it didn't occur to me that together, they could be useful too. Thanks for the link and the pics of the diy parts. Hope more members could benefit from your experience. Thanks! :Smile:

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## juggler

Looks like a good idea. Would be great if can be tested on pressurised CO2. I never thought the rubber tubing can fit the syringe.

But some thoughts:
- the check-valve will still function if wet? I had experience once or twice the check-valves which let water flow back when wet.
- for DIY CO2, most folks have a 2nd bottle of water to filter the CO2 before passing on to the tank. See http://www.thekrib.com/Plants/CO2/co2-faiz.html for example. This 2nd bottle acts as a bubble counter too.  :Smile:

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## richietay

Would say a very innovative idea, may be neater this way compare to bubble counter.

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## kemp

it's really a neat idea! combining 2 into 1. It's really nice of you to show the detailed steps with pictures. Thumbs up for you!

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## dc88

> - the check-valve will still function if wet? I had experience once or twice the check-valves which let water flow back when wet.
> - for DIY CO2, most folks have a 2nd bottle of water to filter the CO2 before passing on to the tank. See http://www.thekrib.com/Plants/CO2/co2-faiz.html for example. This 2nd bottle acts as a bubble counter too.


Really ? OK, I'll keep a watch.
Encourage more to try it and share any observation.
Thanks.

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## magic1980

simply impressive.
think really need to crack the brain a bit.
then all the good DIY ideas will come out.

nice and neat.

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## xtrekker

good idea.. it didn't occur to me .. i have both parts in my junk box , will give a a try. 


cheers

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