# Bell diffuser + powerhead



## l33tgeist (May 8, 2011)

I just set up a 40-gallon long tank, and I put in a Koralia Evolution 750 submersed powerhead at one end for circulation. It's a kickass powerhead, gets water movement throughout the tank, and I thought it would be great if I could get my DIY CO2 outlet hooked into it somehow to get the CO2 to circulate throughout the tank as well. I tried just letting the bubbles go up through the impeller, but that was loud and ineffective because most of the CO2 still reached the surface. Last night I had the idea of making a bell to trap the bubbles over the powerhead, so I knocked something together with the bottom of a soda bottle and ran the CO2 into that, and so far it appears to be working wonderfully. The edge of the bell catches the edge of the outflow current, and the current vigorously agitates the water under the gas bubble in the bell. The real test will be the plants (once I get the lighting online in the next couple of days) but physically it seems like a fine diffusion system. Has anyone tried this before? Any thoughts?


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## niko (Jan 28, 2004)

Wow! Nice!

In my big 6 ft longtank tank I use a "bell" made of a large water cooler bottle cut in half. It's a bit big but it too works very well like yours.









I've planted a lot of plants in front of the "bell" and it's not as ugly as you might think. I found it in the trash and my CO2 diffuser doesn't cost me a dime because I had the pump already!

Good job!

--Nikolay


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