Re: Do I need CO2

Marty Durkin writes...

>I recently setup a DIY C02 injection system by doing the following:
>        1) Dissolved 3/4 cup of sugar in 2 cups of hot water
>           and poured this into a 2 litre bottle
>        2) Added 3 cups of cool water in with the sugar water.
>        3) Dissolved 1 teaspoon of yeast in 1 cup of warm water and
>           then added this to the rest of the solution
>I waited for a few hours until the solution began to bubble in a bucket.
>I then connected this to a valve on the back of the tank.  From the valve,
>I connect airline tubing with a bubble stone at the end of it.  
>If I shake the solution, I get lots of bubbles in the tank.  However, if
>the solution just sits there, I don't get any bubbles at all.  The aquarium
>is in the family room in my basement where the room temperature is about
>68 degrees.  I'm not sure why I get the bubbling in the test bucket, but 
>not in the aquarium.  Could this be due to the cool temperature of the
>room (i.e. the yeast is not active enough at this temperature).  
>Also, the 2 litre bottle is below the tank on the bottom shelf of the 
>stand.  Should I sit it on the lid of the tank?  I also noticed that
>the yeast solution is not foaming like it originally was, and I have
>tried two separate solutions over the past week with new yeast.  The
>end result is the same - C02 in the bucket, but not in the aquarium.

75F would be a better temperature for baker's yeast. Activity is
temperature dependent. Try doubling the concentration of sugar in
the 2 liter bottle. If the water column and hence pressure on the
CO2  is greater in the aquarium than in the bucket, you may have
a leak around the connection to the bottle.

George Booth writes...

>We have NEVER had a nitrogen deficiency in our heavily planted,
>heavily "fished", vigorously growing systems.  By actual measurement, 
>nitrates in one of the tanks will increase by roughly 1 mg/l per day. 
>Keeping nitrates in check requires much effort on our part, to the
>tune of 50% water changes biweekly. 

Are you saying that your nitrates increase proportionally faster than
your phospahates?

John Lobingier writes...
> According to my test results and the chart in "The Optimum Aquarium"
> I do not need it.

The short answer is that you will need to add CO2 unless your fish
are producing an extraordinary amount of CO2. As has been suggested
I'd buffer your water as well.

Dave Whittaker                       ac554 at FreeNet_Carleton.CA
Gloucester, Ontario                  dwhitt at magmacom_com