co2 diffuser right underneath the filter intake? good idea?

[TwoTankAmin]

A few observations:

1. Co2 through the filter in a well planted tank is not an issue as you have minimal bacteria since the plants eat most of the ammonia before the bacteria could.

2. Co2 outgasses to reach equilibrium as noted above, However, this does not happen when there is 0 surface agitation. The natural surface tension of water will block gas exchanges in the absence of aggitation. That is what allows one to naturally increase co2 levels somewhat in a tank by eliminating surface agitation. Of course there are limits to how much one can gain this way.

3. I run my co2 through my Eheim because I had no room inside or outside the tank for diffusers or reactors. It has been running this way since fall of 2002. I have my output end of the co2 pushed down inside the prefilter.

4. Putting the output of diy co2 into a canister intake is an invitation to disaster. Any problems and you can end up sucking the contents of the diy bottle into the tank. Instead place the output underneath the filter intake so as the bubbles rise they get sucked in.

5. One can run added co2 in the presence of surface agitation as long as one pushes it in faster than it will become insufficient due to outgassing.

 

[DGC]

A few observations:
4. Putting the output of diy co2 into a canister intake is an invitation to disaster. Any problems and you can end up sucking the contents of the diy bottle into the tank. Instead place the output underneath the filter intake so as the bubbles rise they get sucked in.

:iagree:

 

[sepehr]

A few observations:

1. Co2 through the filter in a well planted tank is not an issue as you have minimal bacteria since the plants eat most of the ammonia before the bacteria could.

2. Co2 outgasses to reach equilibrium as noted above, However, this does not happen when there is 0 surface agitation. The natural surface tension of water will block gas exchanges in the absence of aggitation. That is what allows one to naturally increase co2 levels somewhat in a tank by eliminating surface agitation. Of course there are limits to how much one can gain this way.

3. I run my co2 through my Eheim because I had no room inside or outside the tank for diffusers or reactors. It has been running this way since fall of 2002. I have my output end of the co2 pushed down inside the prefilter.

4. Putting the output of diy co2 into a canister intake is an invitation to disaster. Any problems and you can end up sucking the contents of the diy bottle into the tank. Instead place the output underneath the filter intake so as the bubbles rise they get sucked in.

5. One can run added co2 in the presence of surface agitation as long as one pushes it in faster than it will become insufficient due to outgassing.

Hey thanks for all the info. Like I mentioned before I placed my reactor right under the filter intake & I take it some of the dissolved co2 water is sucked up through it & comes out from the spray bar. The thing is that the spray bar is just 2 inches below surface & it's making mild semi-whirl on the surface and I don't know for sure how much co2 is lost this way. Maybe I'm better off to place the reactor back in its original position but I believe the reactor isn't powerful enough for my 90 gallon tank & it might not be spreading co2 around the tank efficiently and that's why I placed it underneath the intake hoping for a better co2 circulation.

 

[sepehr]

no matter how well it's dissolved it's still going to want to escape.
reaching atmospheric equilibrium (which it will do sitting still under any conditions except sealed completely air tight) brings co2 concentrations ~3ppm.

think of it this way. in a wine cellar theres a bottle of champagne that's been sitting for 30yrs. no detectable bubbles anywhere. but grab that bottle and run up the stares and co2 bubbles are everywhere... you've disturbed the surface.

or... take 2 10 gallon fire-proof vessels and some smoldering, moist kindling. watch them both fill up with smoke (open tops on both) and then turn a fan to blow across one of them. the smoke is going to dissipate in both of them eventually... but the one with the fan on it is going to dissipate at a much faster rate.

in the first example your surface agitation is just that... moving the bottle and agitating the surface. in the second example surface agitation would be wind... and even without it the smoke (co2) is going to dissipate regardless.

I got it your explanation was crystal clear...cheers