# co2 diffuser



## soap3r123 (Apr 10, 2013)

I'm looking to make a CO2 diffuser for my 10gallon planted. and I have a couple questions 

will this affect my pH or my water in anyway harmful to my fish?

Will a 2l bottle be enough or to big?

Should I add an extra bottle for a yeast catcher?

Any other advice? 

thanks.


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## Fuzz (Jan 27, 2012)

your ph will read differently, this is actually how we determine how much CO2 is in the tank.


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## TheOldSalt (Jan 28, 2005)

Yes, CO2 will definitely lower your pH, and in a 10gal tank it can lower it quite a bit before you know what happened. I know they're expensive, but instead of making one, you might want to get a store-bought one for safety with a small tank.


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## grogan (Jan 23, 2011)

Agreed, why make one when they are cheap on amazon. If you are dead set on making one it can be done though. you can take an old gravel siphon and cut it down to 2-3 inches. Then drill a hole on the the top where the drain tube connects to the drain line. Drill it at a smaller size than your CO2 tubing, so when attached the smaller diameter hole will keep it tight and in place. Cut a small piece of foam that will fit inside the tube and insert it into the bottom end and leave a gap between the sponge and the intake hole of the siphon. After that, you take a smaller power head and attach the return to the siphon intake hole. From there you attach your CO2 line to the small hole drilled into the top of the siphon and install the diffuser into the aquarium. 

This is how it works:

CO2 is pumped into the diffuser and is blasted by the flow of the power head. From there it is mixed with the water until dissolved. Once dissolved it exits through the bottom of the tube where the foam is. The foam keeps fish and shrimp from entering the CO2 diffuser. I have made these before and had amazing results. Since you are using a DIY setup this might actually be a better setup.


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## yannis2307 (Apr 23, 2012)

wait, wait, wait. most filters have a thingy for airline tubing to connect to it right where the water comes out of the filter. if you have an internal filter of course. so if you already have your system up and running, you could connect the final end of the co2 system to that thingy and it will do a pretty good job IME... or you could put the airline tubing final end of the system under the filter's intake, so the filter will suck up the bubbles and blow them out and around... I have found the second to work better, because if you use a DIY CO2 system, when you use the first, the upwards pressure of the water combined with the downwards pressure of the gas your system makes does for a very unstable flow and makes leaks like in the caps of the bottles more possible...


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## grogan (Jan 23, 2011)

Interesting. With a CO2 reactor (what I described) you get complete CO2 saturation. There are no bubbles getting into the tank and therefore not nearly as much escape or waste. The gas cannot enter the aquarium until it is completely disolved into the water column. Also, when using CO2 I would suggest only using an internal filter or canister filter. Hang on the backs often make lots of surface agitation, which allows CO2 to escape. Minimal agitation is best, basically enough to make ripples across the entire surface and therefore still allow oxogen in.


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