From: PLai@cup.portal.com (Patrick L Faith)
Newsgroups: alt.aquaria,rec.aquaria
Subject: Re: [F] Plant Tanks - Organic C02 injection
Date: Sun,  6 Sep 92 11:03:50 PDT
Organization: The Portal System (TM)
Distribution: world
  <16804@ucdavis.ucdavis.edu>

Paul Raulerson
>>In article <65295@cup.portal.com> PLai@cup.portal.com (Patrick L Faith) writes:
>>I was woundering on the C02 level difference between having a large flow
>>of water through a biological filter that removes 02 to give c02, compared
>with straight C02 injection. >
> >                          PLai
>>
>Paul Raulerson writes
>
>It depends, in the average tank, a lot more on surface agitation than on 
>the bio filter. I haven't really found a suitable balance yet myself, and
>I tend to err on the side of the fishies. (i.e. - more O2 than CO2.) 

Sounds like the consenus - when not using CO2 injection , rely on the
CO2 that the fish produced by not agitating the water ( but at the same
time allow enough O2 in the water , the problem being what are the O2 levels
with no surface agitation). I've been thinking of putting 8 Discus in the 100 gallon
tank with about 30 neon tetras ?  Also how much does a fish resperate compared
to what a plant needs? A lot of the nice Discus tanks I've seen in the magizens
have good plant growth ( are these fake pictures - i.e. fish put in plant tanks for
a few hours to take a nice picture ??  - especially with water that is fairly warm 84
degrees compared to what the plants like ) - any Discus fanatics out there know ? 

>One compromise that works fairly well for me is to keep the fish load 
>high, and cut filtration and water movement off for about 8 hours per day,
>specificlly with the lighting at maximum. Doesn't hurt the fishies, the 
>biofilter's don't seem to mind, and the plants grow like crazy. 

This sounds like a good idea, since the plants don't need a lot o CO2 when
they are not resperating.  I was woundering how well the plants handle the
mess from the fish ?

> 9/5/92 15:22 30/1373 jimh@ultra.com (Jim Hurley) writes

>>As an example case, what if i had a 30 gallon drum filled with water and 
>>biobale cycling water to a 100 gallon tank at 500 gph - what could I expect
>>my C02 levels to be ?
> >                          PLai


>I'm not sure I follow what you are saying. If I read it right
>you are claiming that one end product of biological filtration
>is CO2, so what sort of filter will give enough CO2 for
>good plant growth?

>If that is what you mean, your assumption isn't right. As far
>as I know, there are no CO2 byproducts in the biological breakdown.
>Ammonia-> Nitrite-> Nitrate. There are no carbon components and
>the bacteria utilize oxygen, but don't respirate CO2, or if they
>do the amount is insignificant.

>Maybe you are asking if there is a biological filtration system
>that does something like this. In that case I haven't a clue.

Hmmm ... I was hoping out of all those bizare bacteria that a big percentage
where doing something aside from converting ammonia to nitrate.  For example
in a reef tank a lot of the people are running with zero nitrite and ammonia, yet
the bio-filter is suppose to be using up O2 - seemed to me like a lot of O2 was
being used up with out much happening in the nitrogen cycle - but I'm fairly
clueless when it comes to this kind of thing and I'm probably wrong. 


>9/5/92 22:15 68/3436 putzolu@toadflax.cs.ucdavis.edu (David Putzolu)

>It seems to me that there is a mistaken belief that there is some
>some or equilibrium between dissolved oxygen and dissolved CO2 in
>water. I'm afraid that this simply is not so. If you add CO2 to
>water you do NOT drive out (or cause to go up) O2 levels, and
>vice versa. These are simply two different dissolved gases, and
>the only affect they should have on each other is indirect. 

Some people are trading surface agitation for higher CO2 levels ... what I
have heard is that surface agitation tends to "loose" CO2 and "gain" O2 ...
but I don't know why ??? I'm also assuming this "surface agiation" theory
of CO2 lose is the same for wet/dry filters.


>OK, enough talk, now a question of my own for the experts out there:
>When cleaning filtration media, sponges, etc., from in my cannister,
>I commonly use dechlorinated water. I've been thinking though - by
>using fresh water, am I killing the resident bacteria? Wouldn't just
>the osmotic pressure pop the little bacteria, who are acclimated to
>salt water? Would it be best to use water from my tank to do it in  
>order to preserve the bacteria population?

Before I followed the net wisdom and put floss in my prefilter (actually got one
of those things where you can put floss in the drip tray of the wet/dry filter) I had
a canister filter that would get really yucky - so I washed it out with the weekly
water exchange and never noticed a drop off in bacteria and also started to get
some healthy trunicate growth in the thing.

PLai
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