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CO2 injection discussion
Preamble:
KB Koh and I have been discussing his problems with pH swings and unreliable
CO2 injection caused by leaks in the DIY CO2 system. I mentioned my powerhead
method of injecting CO2 which eliminates the leaking problem and I'm
explaining how the efficiency of dissolving CO2 is still very high without
a reactor. I suggested that this discussion was interesting enough that
we could post it on the group for everyone's edification. Here it is in
slightly abridged form. I left in a few interesting bits about wild Bettas
in Malaysia. - Steve
From: spush at hcsd_hac.com
To: KB_Koh at ccm_ipn.intel.com
> Singapore is a country just below the Malaysian state
> of Johor. All the Malaysian aquatic plant farms are in Johor. You can see many
> reference to Johor or south-west of Malaya peninsular in Rataj's book. Penang is
> up north and is more famous for its Discus farming.
Have you been to see these plant farms or Discus farms? That would be a
nice place to visit and very interesting!
> >I have heard that they are growing and propagating the
> >beautiful Madagascar lace plants there in Philippines; have you heard
> >of it there in Malaysia?
> No, I did not hear of them in Malaysia.
Pity! :-(
> >Anyway, since fighting with many leaks, I
> >now use a powerhead (type used for undergravel filters) which has an
> >adapter to attach an air hose for aeration.
>
> I tried experiment with this before but hate it as I don't have a place to mount
> the powerhead in my tank. It also cause a lots of water movement. Do you find
> any problem with water flow to your plant and fishes?
No, water flow is very good for the plants; this circulates water over the
leaves and helps provide nutrients. It also stirs up debris somewhat so it
can be caught by the filter. Its also good for the fishes: exercise! Many
fish like to face into the current and catch small things like food there.
This is the same way fish catch food in the wild. My purpose in using the
powerheads was to create current for the plants; it was just luck which
let me try it for CO2.
> How do you count the bubbles with power head?
The powerhead will burp out a big bunch of tiny bubbles all at once. Just
count the seconds between these burps. Each burp is like one bubble.
The burps are not so regular but I count them and average the
times. I like to have it burp at least every ten seconds. Faster is
no problem so long as the pH has been steadily decreased; not all
at once if no CO2 has been added for days. It works best if I just
add new sugar every week or so and replace some of the yeast water
with fresh. Too much work and I am lazy so it is not done as regular
as I should. I also get late with my water changes and cleaning
of the algae. Still the plants keep growing and the fish look happy.
> The current to the intake of powerhead is strong. Small fish and
> fries would have a problem. Do you see this as a problem?
It could be if the inlet is just a hole and not a larger screen or
tube with slits. On my larger powerhead, there was no screening fixture,
just a rubber adapter for the plastic riser of the UGF. It was big
enough for me to insert the plastic slitted tube inlet from the
end of a whisper power filter (trickle filter). This works fine.
I keep many baby platys in this tank. Instinct makes them stay
away from something which tries to suck them up. New fry tend to
stay on the leaves of plants where they are sheltered from currents.
The problem is strong currents in a small hole such as when
siphoning junk from the bottom of a Betta fry tank with an
airline tube. I sucked up many babies this way because the
change in current is too strong and takes them by surprise.
Also the weak ones stayed on the bottom. It is good to have
some large screening device esp. if it can be removed for cleaning!
Algae and junk collects there and can plug off the pump; not good.
The pump could burn out if no water circulates through it.
My 75gal tank uses this larger powerhead. On my 49gal I used
a smaller one which had a screen adapter for that purpose. The
problem is I tried to save money by using a small one and it
does not create enough current to keep circulation in all the
tank. Also this screen adapter is much smaller and wants to get
plugged up by algae and leaf debris. Better to use a stronger one
I think. I also was careful to look for those which came with
clamps for attaching to the tank side.
If you have one without a clamp, maybe you can attach it with
large hose clamps or the plastic tie wraps used for bundling
electrical cables together, to a piece of wood, plastic or
metal which you can then attach or clamp to your tank.
This method would not do for a breeding tank like for Bettas.
For that I would use some floating plants and no CO2. Have you
kept Bettas? I had hundreds at one time but it was too much work.
The breeding is very fascinating to watch. Too much current would
upset the bubble nest and the fry are not able to swim well.
You know, this discussion is very good and perhaps we should
share this with the digest. I will save a copy and edit it
for the digest if it is all right with you? Thank you for your
response and your questions.
Steve
From: KB Koh <KB_Koh at ccm_ipn.intel.com>
To: Stephen.Pushak at hcsd_hac.com
>Have you been to see these plant farms or Discus farms? That would be a
No. I would love to when I have time, especially to the one in Johor. I read
those from an article on Malaysian ornamental fish industry written by someone
in Malaysian Fisheries Department.
>can be caught by the filter. Its also good for the fishes: exercise! Many
>fish like to face into the current and catch small things like food there.
>This is the same way fish catch food in the wild. My purpose in using the
>powerheads was to create current for the plants; it was just luck which
>let me try it for CO2.
Well, some fish don't like strong current. I know all my other fish like it but
not sure about the pencilfish. They are so slow and graceful. I'm already using
Fluval canister filter and it create some current but not enough to stir up
debris on the other end of the tank. I tried to create the same effect by using
the output bar but the bubble is not fine enough and my output bar is a couple
of inches below the water level. Maybe I'll try to experiment further by moving
my spray bar to the bottom and cap its end so that the spray will be stronger
throughout its length. I can then feed the ... no, no. What am I talking about.
I'll figure that out some other time.
>> How do you count the bubbles with power head?
>The powerhead will burp out a big bunch of tiny bubbles all at once. Just
>count the seconds between these burps. Each burp is like one bubble.
>The burps are not so regular but I count them and average the
>times. I like to have it burp at least every ten seconds. Faster is
>no problem so long as the pH has been steadily decreased; not all
I don't quite get it. The powerhead will draw the CO2 in due to venturi effect.
The CO2 generator will produce at a steady rate. The only way it is to bubble
out is when the CO2 pressure is higher than water pressure. How do you have a
burp when the powerhead is sucking in the CO2? I suggest make a bubble counter
ala Dupla. I can easily make that one.
>I think. I also was careful to look for those which came with
>clamps for attaching to the tank side.
Mine has the clamp err.. those rubber sucker. I still can't find a suitable
place to attach it. It looks so ugly.
>For that I would use some floating plants and no CO2. Have you
>kept Bettas? I had hundreds at one time but it was too much work.
Not now. I kept them something like 20 years ago, caught them from the rice
field.
rgds..kbkoh
Steve wrote:
> >The powerhead will burp out a big bunch of tiny bubbles all at once. Just
> >count the seconds between these burps. Each burp is like one bubble.
> >The burps are not so regular but I count them and average the
> >times. I like to have it burp at least every ten seconds. Faster is
> >no problem so long as the pH has been steadily decreased; not all
>
> I don't quite get it. The powerhead will draw the CO2 in due to
venturi effect.
> The CO2 generator will produce at a steady rate. The only way it
is to bubble
> out is when the CO2 pressure is higher than water pressure. How
do you have a
> burp when the powerhead is sucking in the CO2? I suggest make a
bubble counter
> ala Dupla. I can easily make that one.
The CO2 production is constant; the venturi pressure is not. There's a
lot of bouncing of the water/CO2 level in the plastic tube and when it
hits the venturi outlet, a bubble gets sucked out. I make a wild guess
that this bubble is similar in size to a normal bubble (physical
constants being the same) It doesn't matter. I know I need roughly
so many burps a minute to maintain an acceptable CO2 concentration.
Arrive at that number by the same method as counting bubbles! :-)
Whatever it is that makes water drops and air bubbles (surface tension?)
want to be the same size also makes the burps want to be the same size.
There is just a lot more variation in the size and frequency of burps.
The burp looks like a fine mist of bubbles that shoots out suddenly.
The bubbles don't burst, just float around or sit just at the water
surface. Really large CO2 production (shake the generator) produces
large enough bubbles that they actually do burst; tiny little
droplets pop out of the water just like when carbonated water
efferveces.
> >I also was careful to look for those which came with
> >clamps for attaching to the tank side.
>
> Mine has the clamp err.. those rubber sucker. I still can't find a suitable
> place to attach it. It looks so ugly.
Rubber suckers are no good. Powerhead will fall into the tank. Electrical
short circuit will trip breakers. Powerhead probably ruined.
> >For that I would use some floating plants and no CO2. Have you
> >kept Bettas? I had hundreds at one time but it was too much work.
>
> Not now. I kept them something like 20 years ago, caught them from the rice
> field.
Very neat! But were these the wild varieties or the ones with long
fins that were let wild?
Steve
From: KB Koh <KB_Koh at ccm_ipn.intel.com>
To: Stephen.Pushak at hcsd_hac.com
>The burp looks like a fine mist of bubbles that shoots out suddenly.
>The bubbles don't burst, just float around or sit just at the water
>surface. Really large CO2 production (shake the generator) produces
>large enough bubbles that they actually do burst; tiny little
>droplets pop out of the water just like when carbonated water
OK, now I got it. I thought the bubbles you're talking about are much bigger
like those use for aeration. So it will release fine bubbles. Yeah, I have seen
this happen before during my previous experiment. I guess I'll try it again and
see how I like it. If I build a bubble counter, I think the bubbles would be
bigger which is not good as it rise to the surface too fast. Come to think of
it, I never use my bubble counter anyway. I just use the water level in the bell
reactor as an indicator. My mixture has also been consistently lasting for 2.5
week. I use 1.25 liter bottle with 1 cup of sugar, half teaspoon of yeast and 1
teaspoon of Baking Soda. I'm alternating two bottles every two weeks in a gang
connection.
>> Mine has the clamp err.. those rubber sucker. I still can't find a suitable
>> place to attach it. It looks so ugly.
>Rubber suckers are no good. Powerhead will fall into the tank. Electrical
>short circuit will trip breakers. Powerhead probably ruined.
Wait a minute. Are you talking about external powerhead or internal one? I have
the internal powerhead that is use submerged.
>> Not now. I kept them something like 20 years ago, caught them from the rice
>> field.
>Very neat! But were these the wild varieties or the ones with long
>fins that were let wild?
Unfortunately the wild one, the fins were not that long as those from Thailand.
They are dark black with some rainbows of colors thrown in on light reflection.
You can also find some very colorful one once in a while. The later does not
belong to the Betta Splenden species. Forgot the name but it was featured in a
British mag a month or two ago.
rgds..kbkoh
To: KB_Koh at ccm_ipn.intel.com
> I never use my bubble counter anyway. I just use the water level in the bell
> reactor as an indicator.
I don't use a reactor at all with the powerhead.
> >Rubber suckers are no good. Powerhead will fall into the tank.
> Wait a minute. Are you talking about external powerhead or internal one? I have
> the internal powerhead that is use submerged.
Mine cannot be completely submerged. Even if it could, the suction cups
eventually release unless you cemented them on with silicone glue.
Steve Pushak - spush at hcsd_hac.com - Vancouver, BC, Canada
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