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Re: CO2 losses due to trickle filters

> Date: Mon, 28 Apr 97 13:44:06 PST8
> From: spushak at CCGATE_HAC.COM
> [George will probably correct me ;-) ]

Hey, no problem, glad to help. <g>

> properly sealing the sump to create a high CO2 environment in it is
> also going to create an environment without O2 since oxygen cannot
> diffuse into the chamber without CO2 diffusing out just as fast. 

I guess you've never seen a trickle filter at work.  The sump is not
the part that causes CO2 loss.  The culprit is the media chamber where
the water trickles through the biomedia with the attendant turbulence
and outgassing of CO2 and "ingassing" of O2.  The media chamber cannot
be effectively sealed since the inrush of water also pulls in lot's of
air (and O2).  

> The lack of oxygen probably defeats the purpose of the filter
> (nitrification) 

It would if there was a lack ...

> I think George advocates sealing up the sump chamber

No, George advocates "not pumping extra air into the media chamber".

In the "old" days, people would hook up an air pump hoping to make
sure the media chamber was well aerated, providing good O2 levels and
helping nitrification.  This is not needed, especially in a planted
tank.  I personally don't think a pump was ever needed anyway due to
the air being pulled in from water movement. The air pump will
definitely remove CO2 (our usage was cut in half when we finally
turned off the darned noisy air pump).

> If George says you can do it, you can believe it but make sure you get
> that advice from the horse's mouth.  [sorry George, no pun intended
> ;-) ]

Yeah, right. 

George "At least, it's The Mouth"