Re: [APD] CO2 Reactor Questions

["S. Hieber" <shieber at yahoo_com>]

--- rockel <rockel at attglobal_net> wrote:
>   I am running DIY CO2 through the intake on  my Ehiem
> 2215 canister on 
> my 35 gal. tank. I am losing a lot of CO2 through the
> spray bar and 
> would like to build a reactor. Through the archives I
> found this site 
>  http://www.aquaticscape.com /articles/co2reactor.htm 

That's a good basic design. You can use a piece of clear
PVC for the main chamber but it's not necessary and clear
PVC is very expensive.

> Can the reactor be used with DIY CO2?
So long as the DIY is producing enough pressure to push the
gas into the reactor -- and it should, on the outpput tube
from the filter the water pressure should be only a couple
of psi or so.

You might try putting the reactor on the intake line of the
filter -- less water pressure on the intake side.

> I assume by "inline", you cut out a piece of the plastic
> tubing approx. 
> the length of the reactor between the intake and the
> canister and 
> install the reactor where the piece was cut out?

Best to leave some extra length; check what turns/curves
the tubing has to make. Sharp curves can eventually cause
the tubing to squeeze and restrict water flow. Sometimes
it's easier to have extra length and let the tubing coil
one loop to make a turn rather than turn sharply and crimp.

> Do you  need the airline connector or can you still have
> the CO2 go into 
> the intake of the canister in the tank? 

Not much pont to the reactor then. The canister and the
reactor are pretty much the same thing, in a sense, a
chamber where the CO2 and be absorbed into the water
running through it. But you don't *have* to use the air
connector type fitting. You could drill a hole jsut large
enough that you can squeeze an length of airline tubing
into it, seal it with epoxy airline. You just might want to
seal with epoxy even if you use the fitting. ;-)

> By having the
> airline on the 
> reactor are you just taking a tube out of the tank for
> appearances or is 
> there another purpose for the location on the reactor.

You could have a reactor like this inside the tank but why?
With this kind of reactor, the CO2 can't get out except by
being abosrbed into the water.  You get 100% absorbtion.
With this kind of reactor, the only way that won't happen
is if 1) the CO2 flow rate and water flow rates aren't well
matched and the tube fills with CO2 and 2) the water flow
rate is so strong that it "blows" bubbles out the bottom.
Having the bioballs or plastic mesh inside help to avoid
that problem. But you might want to Tee off the main filter
line and run that to the reactor. I don't think you'll need
the full flow of the 2215 to get all the CO2 into a 35g
tank. In fact, if the tank is covered and you don't have
surface turbulence, you can get away with a very small
powerhead to give you waterflow to the reactor. 

I have a reactor from Tom Barr that works that way and it
cut my CO2 use by about 4-fold compared to some other
devices I had tried. 5 pounds of CO2 can easily last more
than a year.

When using the PVC cement to joint the main pieces, be sure
to be in a very well ventilated location, preferably
outdoors or under a hood with an exhaust fan.

And test the unit for watertight integrity before
installing on your aquarium -- better to find any leaks at
the sink.

Good luck,
Scott H.


=====
S. Hieber

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