DIY CO2 with powerhead

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Blucat

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Joined
Jan 7, 2005
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i have been reading up about DIY CO2 systems, and i sort of understand it. I have a powerhead f ilter which takes in air and then blasts it out into my aquarium water to create aeration. I was wondering if it could be turned into a simple CO2 setup like my picture? would that set up work or is there other stuff i need in it?

also, does CO2 effect algae? the powerhead is my only source of aeration. if i do turn my powerhead aeration into part of a CO2 system, will i lose aeration? is CO2 a form of aeration?

thankyou for any help, please bear with me and my funny drawing, i quite don't know much about plants and that and about the names of the powerhead parts and about CO2 systems. 8O
 

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The problem is most of the CO2 will still go right to the surface as large bubbles, meaning you'll not get much dissolved in the water.
If you can attach a gravel vac tube to the output, so it keeps the bubbles spinning in a chamber of water for a longer period, you'll get better dissolve rates.
 
My plants are growing like crazy from my DIY CO2.... unfortunately, the Algae is growing faster.

Since adding CO2 i have a couple plants that became encased in algae (stag algae i think).
 
Connecting to venturi plug doesnt force siphon of bottle's contents? I thought siphon created from fast water flow is the same concept that powers Python? Just curious/TIA
 
czcz - good point. I've never used powerheads with venturi's (or I plug up the venturi) so you could be right, that it'll create too much suction.
However as long as the DIY canister can't collapse (use really thick plasic or glass jugs..no cheap 2liter Coke bottles) it should be ok.
 
I have no idea what a venturi is either - but I have a similar setup as you describe (2 litre bottle with a powerhead attached. It doesn't create enough suction to pull anything out - but I do have a smaller bottle in between the powerhead and the 2 litre bottles. I also have the check valves.
 
Thanks, malkore.

In this case I meant venturi as the aeration hole you attach tubing to with some PH. Sucks air in because of fast water movement/low pressure, which goes through output. I thought this is what makes python work over long distances, and was inclined to think decent PH moved more gph than my faucet, but Im no fluid dynamics expert (just pick up what I can since entering hobby). Venturi attachment differs from powered diffuser/gravel vac designs I've seen in that the latter simply has compartment where water moved and output of diffuser is in same area mixing. Example: http://www.csd.net/~cgadd/aqua/diy_reactor.htm Thanks for info black udder. Sounds efficient if output of PH is then broken up with sponge/bioballs/gravel vac method per malkore's first post. I might try this later.
 
so my setup plan only has the CO2 source and the diffuser.

do i need a reactor between the powerhead and t he CO2 source? how does the reactor work? does the CO2 enter the reactor, and then go into the powerhead?what is a good DIY CO2 reactor i can make?

how do i stop suction? will the CO2 provide aeration?
 
Here's the one I made and use:

http://www.qsl.net/w2wdx/aquaria/diyco2.html

The powerhead pulls water into the Python gravel vac and the CO2 is pushed into the same tube. The CO2 is churned with the water and the tiny bubbles usually come out from the bottom.

Works well... I believe I'm going to try to continue to use it with a pressurized system one day.
 
will i need extra aeration though? see if i turn my powerhead venturi into part of CO2 setup, i lose the use of the venturi drawing in normal air to expel in the water. will the CO2 provide enough oxygen for the fish? or will i have to buy an additional venturi?
 
As long as there are ripples on the surface gas exchange is occuring. Having said that with CO2 you want to minimise this.

If you have a heavily planted tank with sufficient light, the plants should keep O2 levels up.
 
If you have a heavily planted tank with sufficient light, the plants should keep O2 levels up.

Well, the problem is that at night, plants stop photosynthesizing and start respiring, so they actually draw down oxygen levels. I think you'll be fine, I don't know your tank situation but you'd need a lot of fish and plants to drop down O2 levels to the point where the fish are suffering.

CO2, however, is denser than normal air, which could be a problem if you have zero surface agitation on your tank. A layer of CO2 forming above the water in your tank may limit the ability of atmospheric oxygen to diffuse into the water, which would be a huge problem.

What I would do is have a inlet that mixes the CO2 with atmospheric air. You are going to be sucking way more air than your CO2 reactor can produce anyhow, just mix your CO2 inlet with regular air. Then you are still aerating while you add CO2 to the tank.
 
i have a form of surface agitator thingo. it agitates my surface. i am concerned on oxygen levels as oxygen level is what keeps my tank cool and is what helps my fish thrive in my water. you see i live in australia and it gets very hot, and even now that it is almost winter, the water temp is only 1 degrees lower than summer. in my city fish deaths have been caused from heat. i have extreme excess aeration and i can't remove it at all.
 
i have a water pump (pumps water through a filter media in the hood) and a sponge filter on t he powerhead
 
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