DIY simple Co2 for planted aquarium

you can use airstones but make sure you use the micro kind that create really small bubbles. Typical airstones don't make the co2 bubbles small enough. The smaller you can get the bubbles the more you increase the surface area of the spheres (greater area to volume ratio) which make it much easier to be absorbed by the water.
 
i use a wooden air stone it makes the bubbles much smaller then them other type

think its called lime wood
 
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