Re: CO2 woes, Oh-no not Ammonia again!

> From: Sharon Stewart 
> Subject: CO2 woes
> Before the co2 was  added the tank water ph was swinging out of control (7 to 8 one day 8 to 9 the
> next) and KH was dropping to 2.  I have the controller set to turn on the co2 at
> 7.3  w/ a bubble a second.  It works great for a day or so and then the ph
> starts climbing to 7.6 and above.  I keep swearing at the reactor, but maybe
> that isn't the culprit?  The Sandpoint reactor has been very difficult for me to
> regulate. When I first got it, it was next to impossible for me to find a
> balance between enough water flow going through the reactor and blowing the co2
> out of the reactor.  I'm using an Aquaclear 802 powerhead (the 301 wasn't
> powerful enough).
>    This is driving me crazy, every day I'm fiddling with the co2.  Should I just
> not worry about the rise? Or is my reactor just not very efficient? If it is my
> reactor, can anyone suggest a better one?
There are a few things that could be wrong with your setup Sharon. However this 
would be hard to determine without visual inspection of your system and some
experimenting. Your water is very soft and as such doesn't have much buffering 
capacity. pH swings can be often eliminated by increasing the carbonate hardness
to say 5 on the German scale. Aquaria FAQ offer plenty of suggestions how to
do that and often inexpensively. For example Dupla recommends KH of 10 dKH.
    I was at the friend of mine a few weeks ago who had the very same problem 
as you have described. He was also using R/O water filtration so his water was 
also very soft. As soon as I saw his system I knew what was his problem. He had 
his reactor in the HORIZONTAL position. Of course his bubbles just went through 
the reactor only partially dissolved. The water should be comming into the 
reactor from the top and exiting through the bottom. You likely have it set up 
properly, I have only mentioned this to illustrate how many things (even really 
trivial ones) can go wrong in ones setup.
Good luck.

> From: gtong at sirius_com (G.Tong)
> I don't keep discus but I do keep goldfish. On the Goldfish List, many of
> us maintain base water where ammonia is potentially more of a problem. The
> relationship of ammonia/ammonium to water temp is also interesting to me
> because we tend to have more problems with goldfish in the summer months
> when the tank temp rises. If the filter were already "saturated," then
> faster metabolic activity in the fish plus an increase in the rate of
> ammonia to ammonium could cause more stress on the fish.
I know a lot has been said in the recent posts about ammonia/ammonium but I 
would just like to add the temperature variable into the preceding discussion 
for completness sake.
Total                           Level of toxic ammonia at pH...
level ppm         6.0              6.5             7.0            7.5            8.0
1.0                  0.000        0.002           0.006        0.019       -0.057
1.2                  0.000        0.002           0.007       -0.023       -0.069
1.5                  0.000        0.003           0.009       -0.029       -0.086
2.0                  0.001        0.004           0.012       -0.038       -0.114
4.0                  0.002        0.008          -0.024       -0.076      *0.229
6.0                  0.003        0.011          -0.036       -0.114      *0.342

Note the values in the above table without a sign preceding it are harmless 
concentration of toxic ammonia, values with the "-" sign are critical and the 
values with the "*" sign are highly toxic. The preceeding table should also be 
adjusted for the temperature since the values above are only valid for the 
temperature of 24 Celsius. For every 1 degree Celsius higher or lower the above 
values increase or decrease respectively by approximately  4%.

For more info and further reading (Krause/1990  Handbuch Aquarien-Wasser)
Sorry, it is written in German only! Dupla's follow-up book "The Optimum 
Aquarium Control" has also quite a few interesting facts regarding the water 
chemistry in the aquarium.

Franc Gorenc           franc at golden_net
Kitchener, Ontario     http://www.golden.net/~franc