hoppycalif

You need to leave air at the top of the water, otherwise the CO2 would tend to lift water out just as a trail of air bubbles lifts water. The venturi on the outlet of a powerhead is not a good place to add CO2, and it is a very bad place to add DIY CO2. That venturi generates suction which would try to suck the DIY bottle contents into the tank. And, the CO2 bubbles would be too big, using that, to get much dissolving of CO2 before the bubbles float to the top of the tank.

The best way to use the powerhead as a CO2 reactor is to inject the CO2 in the powerhead inlet, so the pump rotor chops it up into small bubbles. If you remove the pump rotor and drill a few holes in each blade, the bubbles will be much smaller after going through the powerhead.

timwu12

sounds like a plan! thanks hoppycalif!

however, how should i point the deflector on my powerhead? Right now it's angled up about 45 degrees or so and breaks a little of the surface with a hill of water that runs up, out of the surface by a couple centimeters and then back down (just like a little hill of water that's from the powerhead) is that ok positioning of the powerhead for co2 dispersal or should i flip the deflector all the way down to 0 degrees so that it just gets pumped straight out without it breaking the surface? What if i turn the deflector upside down so the water pumps downwards? Is that a bad idea?

hoppycalif

If you are adding CO2 to the inlet of a powerhead you will get CO2 mist out of the powerhead. That mist should be directed so it hits as many plants as possible, preferably low in the tank. I think it is a good idea to have a little ripple on the water surface, too, but I do that with the canister filter outlet. I have that outlet near the top and angled so the surface is just slightly rippled.

timwu12

what happens when you've made the mix, hooked it up, but realize you added a little too much water so that some of the foamy stuff got sucked into the tube and expelled into the tank? I've since taken the mixture and poured some of it out of the bottle, but as for the water conditions and the fish, how are they going to be affected? Thanks

hoppycalif

I would do a 50+% water change. The big bubble counter or "muck catcher" is needed to stop that stuff from getting to the tank. Also, with DIY CO2 it is a bad idea to inject CO2 in a way that will cause suction on the CO2 line.

natdc2

I have a question. How many bottle of 2L should I use for a 30 gallon? Is one sufficient enough to produce the require amount of co2 by injecting the co2 into a powerhead. If not, should I use two and deliver it into a powerhead also? Thanks you.

hoppycalif

The reason for using more than one DIY bottle is to stagger the start times, so at least one is always producing an adequate amount of CO2. That keeps the amount in the water more nearly constant, which helps prevent algae from starting.

natdc2

Oh ic. The reason why I asked is because I was afraid of producing too much co2 with 2 2l bottle, thus harming my 20+ tetras at night.

hoppycalif

You can get a drop checker pretty cheaply, or make one, and that will tell you if you have too much CO2 for the fish to tolerate. See the sticky here.

CraigThor

Anyone make this on a larger scale say from a 5 gallon jug?

Craig