"Tony Volk" wrote in message
...
After listening to a lot of opinions, I've decided to stick with my
30-35% weekly water changes (at least until I get a python), but to add
some
CO2 for my high-load 55 gallon (80watts). I made up a DIY CO2 system with
one 2L CO2 bottle in order to go slowly before adding a second CO2 bottle
(through a t-joint that currently has one arm sealed). I had problems
with
the seal at first, but then just made a smaller hole on another cap, so I
now have plenty of CO2 coming into the tank through 1/4" silicon tubing.
In the short term I got an airstone (useless) and a clear plastic bell
to allow passive diffusion. This isn't working too well, as the CO2
builds
up and occasionally bubbles to the surface when the bell fills (the bell
is
right beside my large HOB filter intake, I also have a second smaller HOB
filter on the other side of the tank). So my next step is to find a good
way of diffusing the CO2 into the water (I keep the water level high to
reduce surface agitation). I like the ease of diffusion compared to
reactor
methods, especially since my wall plug is already bearing a heavy load!
So
does anyone know of a good diffuser I could build or buy (in Canada)? I'm
looking at one from Big Al's:
http://www.bigalsonline.ca/catalog/p...3&pcid 1=3349

Does anyone have any experience with how efficient these style diffusers
are? Anyone know of good data on how efficient the various diffusion
methods are? I don't need ultra-high levels of CO2, but I haven't seen
any
significant change in my pH or plant growth under my current (and
admittedly
half-assed) set-up. As I said before, I prefer the diffusion method, but
I'm open to building/buying a reactor if that's truly a much better way of
going about it. I certainly don't see my current bell set-up doing much
if
I add a second DIY bottle of CO2! Thanks,

Tony


Tony,

I used to do the DIY yeast CO2 injection directly into the uplift tube of my
HOB filter for my 39 gal tank. With that setup I was able to achieve about
18 ppm CO2 saturation. I found that I could get a good 8 days of production
from a 64 oz mixture (juice bottle) and so I would change the mixture out
every weekend with a new batch that was started 24 hours prior (new batch
usually mixed up on Friday night). That way, every Sat or Sun the aquarium
got a new charged up batch of CO2 that *could* last 8 days.

I upgraded to a 70 gal tank and tried to keep up the CO2 saturation with two
bottles of DIY yeast mixture and couldn't do it. To this day I do not know
why but the advice on this newsgroup was that beyond 39 gallons, DIY is not
worth it.

On my 75 gal I had about 2.5 wpg of lighting and so stable CO2 was crucial
to steady growth and nutrient uptake. As you can imagine, I had a
disastrous break out of algae due to fluctuating CO2 and corresponding
fluctuations of nutrient uptake by the plants. I broke down and spent US
$125 for a pressurized system and have never looked back. I recommend it if
you can afford it.

As far as a reactor goes, I had the best success with a power head and
gravel vac tube combination. There are many sites that describe the DIY CO2
reactor. The best efficiency was when I angled the vac tube at about 45
degrees. I think the reason for this was two fold. 1) the bubbles seemed
to stay in the reactor tube longer at this angle and 2) the angle promoted
the dispersion of the saturated CO2 water around the tank. Vertical seemed
to concentrate the CO2 in only a portion of the tank.

You might experiment with your DIY CO2 setups using a power head reactor but
I believe your success will be marginal because of the size of your tank.

HTH,

DJay