On Sat, 23 Sep 2006 00:11:38 -0700, southpaw wrote:

On 22 Sep 2006 09:27:21 -0700, "Tynk" wrote:


There's no point in letting the CO2 just bubble to the surface, you're
probably losing about 99% that way - no bubbles should actually reach
the surface, they should disolve before they get to the top.
Use a reactor or diffuser of some kind.

Is a diffuser necessary in a smaller tank? Right now I'm running the
Co2 through an airstone, and the Ph only dropped from 7.3-7.4 to
neutral. I'm thinking maneuvering the airstone closer to the filter
intake tomorrow might be a good idea. What are some DIY mini diffuser
designs?

Regardless of the size of your tank, whichever method you use, the
idea is to get all the CO2 disolved into the water, and to distribute
the dissolved CO2 evenly in the tank water. Ideally, there should not
be any CO2 bubbles breaking the surface of the water.

I use 2 Aqua Medic 500 reactors. I use the out output of my eheim 2217
cannister filter to drive 1 of them, the other is the AM500-M which
has a built-in powehead.

If you move the airstone close to the intake of your power filter so
that the bubbles enter the intake it should help breakup the bubbles
and diffuse them, do note though that the output of most power filters
are located at the top of the tank, you may want to consider turning
the spraybar output down towards the middle of the tank to help even
distribution of CO2. I have read that on occasion, a buildup of CO2
can cause a CO2-lock in the power filter (like a big bubble of CO2
around the impeller) which can cause the filter to fail.

I only use CO2 when the lights are on as plants do not use CO2 unless
there's enough light, it also give the fish a break from quite high
levels of CO2. I do note that a parrot fish that was given to me is
much less active when the pH ges close to 6, I'll proably swap him at
my LFS, the anglefish don't seem to mind.
I still loose a little CO2, but that's probably because I drive them
quite hard at around 8 bubbles/sec. This gets my pH down from around
7.2ish to 6.2ish within an hour of the lights coming on.
I have no experience of diffusers, but they are well regarded.
If you go to http://www.barrreport.com/forums/index.php?
Tom describes a DIY reactor he designed.
You'll also find just about everything you need to know about growing
plants and CO2.

Good luck
Pete