From: putzolu@toadflax.cs.ucdavis.edu (David Putzolu)
Newsgroups: alt.aquaria,rec.aquaria
Subject: Re: [F] Plant Tanks - Organic C02 injection
Date: 6 Sep 92 05:15:17 GMT
Followup-To: alt.aquaria
Organization: Department of Computer Science, University of California, Davis

In article <1992Sep5.222254.8301@ultra.com> jimh@ultra.com (Jim Hurley) writes:
>In <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.  i.e. how big of biological filter do i need
>>for a 100 gallon dutch tank compared to mechanical c02 injection system to
>>maintain a decent CO2 level ?
>
>>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.
>-- 
>Jim Hurley --> jimh@ultra.com  ...!ames!ultra!jimh  (408) 922-0100
>Ultra Network Technologies / 101 Daggett Drive / San Jose CA 95134

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. 

The only ways I can think of increasing CO2 content in water
are the following, ranked in both expensiveness and effectiveness:
1) Buy a CO2 injection unit. Lots of CO2. Happy plants, very unhappy
   wallet.
2) Have a fair sized animal load - animals respirate, consuming
   O2 in the water and giving off CO2. Of course, now you have to
   deal with taking care of fish as well as plants.
3) (Might work) Dissolve lots of regular air into your water. Since
   air has CO2 as one of it's component, hopefully some of it will
   go into the water. I don't know if an air stone would do the
   trick though. Maybe a _very_ fine one. You might want to try
   making a chamber with lots of air in it that gets contact with
   lots of water - like the reaction part of a protein skimmer.


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?

Thanks for any info....

| David M. A. Putzolu               | putzolu@cs.ucdavis.edu              |
| Senior Undergraduate              | op disclaimer(opinion : ptr mine)   |
| Computer Science and Psychology   |      Money? Who needs money?        |
| University of California at Davis |          I've got fish!             |
From: booth@hplvec.LVLD.HP.COM (George Booth)
Date: Thu, 3 Sep 1992 18:01:07 GMT
Subject: Re: Nitrex Box
Organization: Hewlett-Packard Co., Loveland, CO