# Flow Rate for Adequate CO2 Distribution?



## DGalt (Jul 1, 2008)

From my understanding, a big part of the CO2 aspect of a planted tank is making sure that there is adequate flow in the tank so that the CO2 is distributed around the entirety of the tank. So what flow rate should you be shooting for?

I have a 15 gallon tank with an AquaClear 50 rated at 200 gph. I use a Hagen Elite Mini underwater filter (rated at 58 gph) as a means to get the CO2 into the tank. I'm wondering if I should get a stronger powerhead though. 

Also, does the position of the powerhead in relation to the main filter make a difference? For example, should I have the output of the powerhead under the output of the AquaClear? Or should I have them perpendicular to each other? Or am I just being a crazy person obsessing over nuances that don't produce any significant differences in results?

I'm just trying to think of what will create the best distribution of CO2 in the tank. 

thanks


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## davemonkey (Mar 29, 2008)

The answer to your questions is...it depends. Flow will be interrupted/absorbed by plants. So, you should position you outflows in the way that you get good circulation throughout your tank based on your plants position/height/density/etc...

It's not so much 'gallons per hour' as it is 'least restrictive flow' to get a good current through the scape. It sounds like you have plenty of flow, so I wouldn't sweat too much over it. Just make sure you don't have any dead spots where the water is completely still.

-Dave


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## rodrigaj (Aug 17, 2008)

Watch for plant movement. If you see it, you've got good circulation.


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## Philosophos (Mar 1, 2009)

Perhaps try modding that submersible filter for a needle wheel. I'm working on doing the same right now. It's supposed to offer something like 30-50% more efficiency over disk diffusion.

-Philosophos


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## DGalt (Jul 1, 2008)

The submersible I have right now doesn't have the capability (the impeller wouldn't like being clipped), but I ordered a Rio 180 (should be here this week) just for that purpose


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## Philosophos (Mar 1, 2009)

A rio 180 is exactly what I'm using right now in my 20g. The little flow attachments make for some nice distribution options. They've even got a loc-line like fan return nozel in there. The impeller cut very easily with a hobby knife. Scissors didn't do it, even using very sharp micro tip fly tying scisors. The intake is really easy to mod for- one hole drilled, no need to use adhesives.

-Philosophos


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