# DIY CO2 into HOB filter intake.



## colio (Dec 8, 2012)

Hi all, 

I am running a very simple DIY CO2 setup, just a coke bottle (cleaned of course) with an airline tube. Some day I hope to make a better DIY setup with flowback protection and a bubble counter, and proper diffuser, but this is what I am stuck with for now. 

For diffusion, I have read a lot about putting the CO2 into your filter intake. But I am not sure if that is mainly for canister filters (another "maybe someday" sort of thing). 

So, is it sensible to put my airline tube into a HOB filter intake to diffuse the CO2? 

Additional info: 35 gallon tank with aquaclear 300 filter (rater for 70 gallon tank) with reasonable downflow/water movement from the filter.


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## Fish on the Mind (Feb 9, 2012)

I have done this on smaller HOB pumps (Aquaclear 70). It tends to be a bit loud and it probably make the impeller and shaft wear down quicker but it will work.


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## sightlysun (Jun 14, 2012)

I wouldn't put co2 into HOB filter either, you'll waste alot of co2 this way. I put mine at the side across from the hob filter, with a diffuser i got from AI for like $5(which works with diy co2). 
Besides i find it unnecessary to have a bubble counter with diy co2, just make sure you seal the bottle good and redo the yeast sugar solution every 2,3 weeks. You can also pick up a check valve at big als or petsmart for like $3

Aaron.


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