People love CO2 Diffusers but don't use air stones..?

  • Get the NEW AquariaCentral iOS app --> http://itunes.apple.com/app/id1227181058 // Android version will be out soon!
W

wrek

AC Members
Dec 20, 2010
78
0
0
So I have a question. People say you don't need air stones (regular air injection) in your tank because the surface area of the tank and good quality water circulation via pumps, etc., exchange more oxygen than an air stone could.

Well I don't use air stones and have never had a problem with fish. I only use air in one tank, which is a small hospital tank and it's usually empty with just nice calm water and air.

So then plants. People swear by co2 diffusers to help plants grow. Well if oxygen stones don't help fish, why do co2 stones help plants?

I don't blow co2 over my house plants and they do just fine... granted they get a lot more nutrients from the soil than I think aquatic plants might be getting from sand (I don't use substrate for plants) but still, why the co2?
 
Squawkbert

Squawkbert

Senior padder
Oct 3, 2006
3,417
2
38
60
ST.L area
www.aquaticplantcentral.com
Your house plants have ready access to ~300ppm CO2 in air. In aquariums, gaseous/water equilibria leaves about 3ppm CO2 in water. That is not enough for plants, especially if they use that up and have to count on slow diffusion to compensate for their consumption.

Airstones (oe having a filter or power head cause at least a slight constant ripple on the water surface) actually help maintain that 3ppm of CO2 if they are used, but that will still leave CO2 as a limiting factor for plants once they have adequate light.

Check out www.RexGrigg.com, more complete, concise answers await you there.
 
W

wrek

AC Members
Dec 20, 2010
78
0
0
I'm still not buying it... bubbles from a pressurized source are more easily incorporated into water because why?

Adding CO2 to water is done by pressurizing the water, not the co2.
 
Lab_Rat

Lab_Rat

Merry Christmas!
Dec 3, 2009
2,535
0
0
Deep South
wrek said:
I'm still not buying it... bubbles from a pressurized source are more easily incorporated into water because why?

Adding CO2 to water is done by pressurizing the water, not the co2.
Click to expand...
CO2 diffusers create very small bubbles, so there is more surface area and the CO2 can pass into the water better. Airstones create large bubbles and their main function is to break up the surface of the water, allowing for off-gassing of CO2 and increased oxygenation. The small bubbles from a CO2 diffuser when hooked up to pressurized CO2 are CO2, not atmospheric air.
 
Slappy*McFish

Slappy*McFish

Global Moderator
Staff member
Feb 18, 2002
7,835
48
75
Raleigh, NC
Yup, glass diffusers create tiny co2 micro bubbles that dissolve rapidly in water.
Bubbles released by airstones race to the surface and pop creating surface agitation and movement. This action is what aerates and oxygenates the water much more so than the the actual bubbles. The airstone also creates a current as the bubbles rise and is useful for creating water movement within the tank, as well.
 
rockhoe14er

rockhoe14er

AC Members
Jul 19, 2010
2,043
0
0
37
Richmond VA
Real Name
Sean
Squawkbert said:
Your house plants have ready access to ~300ppm CO2 in air. In aquariums, gaseous/water equilibria leaves about 3ppm CO2 in water. That is not enough for plants, especially if they use that up and have to count on slow diffusion to compensate for their consumption.

Airstones (oe having a filter or power head cause at least a slight constant ripple on the water surface) actually help maintain that 3ppm of CO2 if they are used, but that will still leave CO2 as a limiting factor for plants once they have adequate light.

Check out www.RexGrigg.com, more complete, concise answers await you there.
Click to expand...
actually co2 concentrations in air is only 3 ppm. co2 concentrations in moving water is also 3 ppm. The difference is that gasses move 1000 times slower in water than they do in air. So aquatic plants have to spend much more energy to obtain co2 than plants that have direct access to atmospheric air.
 
dundadundun

dundadundun

;sup' dog? ;woof and a wwwoof!
Jan 21, 2009
4,295
2
38
S.E. PA
rockhoe14er

rockhoe14er

AC Members
Jul 19, 2010
2,043
0
0
37
Richmond VA
Real Name
Sean
dundadundun said:
idk...

p.s. we're usually chasing somewhere in the 15-40ppm range depending on goals.
Click to expand...
wow that's so weird. I've read that atmospheric concentration of co2 is around 3 ppm. If it's around 300 ppm that would lead me to believe that we wouldn't have to use pressurized co2 because all we would need is to equalize the co2 concentration with the atmosphere using just an air stone to provide our plants with adequate co2. idk maybe i'm missing something.
 
You must log in or register to reply here.
zoomed.com
hikariusa.com
aqaimports.com
Store
Top Bottom