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Re: [APD] Re: CO2 probe & inline heater/sumpeople find differences

Glee?  If sumps are the homerun kings of filtration, then
there's no real joy in mudville -- I expected the sump to
have much less CO2 impact than it does. 

Re George's rather well noted experiments on CO2 use and
sumps, I don't think I contradict any of his data -- but
maybe the apparent conclusions. You are not misinformed but
I think there's more info. 

I've spoken about this with others and someone, I forget
who just now, ran some numbers. George's tank without the
sump appeared to have been shedding more CO2 (was less
efficient at conserving CO2 in the water) than 150g
aquarium without the sump. My tank with a sump uses about
twice as much CO2 to maintain the 15 ppm but about 4 times
aas much to maintain 20 ppm. Note: if I try to get up past
15 ppm, the amount of CO2 required increases dramtatically.
It does not appear to be a linear relationship. A credible
hypothesis might be that, under a given condition (set-up),
there is a max amount of CO2 that the water system will
"hang on to." As you approach that level, or when you try
to go past it, then CO2 use increases dramatically. With a
sump that level is much lower than with various cansister
set-ups. I noted similar results consistent with this
hypothesis using Marineland Biowheels. I have also noticed
a similar sort of thing comparing an Eheim diffuser versus
a Tom Barr external reactor on a 30g aquarium.

Both the "trickle-chamber" side and the "sump chamber" side
of my sump are covered with well fitting lids that I made. 
Basically, the edges are rabbited to ensure that any
warping of the lids will not cause leaks. Also they are
reinforced to resist warping.

The overflow originally was an Amiracle (U-tube style
siphon) which came with a lid. I am now use a CPR overflow
(integral rectangular siphon chamber), which came with a
lid. The amiracle style is essentially a low volume/high
velocity siphon -- the CPr is a high volume/low velocity
siphohn. The diff overflows had no noticeable effect on the
CO2 use. However, the CPR is much quieter than the U-tube

[[[[As a side note, the CPR's lower velocity, while quieter
in operation, tends to not evacuate the air bubles that get
into the siphon. Accumulation of bubbles can be a problem.
This is especially so if there is a power outage. Safe
operation of this style of overflow, imo, requires some
method of pumping out the accumlated air.  I use a Toms
AquaLifter (a small diaphragm water/air pump) running
whenever the sump system is running. This keeps the CPR
purged of air -- it works great. The AquaLifter will even
start a siphon that is completely lost provided both sides
of the overflow contain water high enough to cover the
bottom of the siphon chamber -- which it does even when you
completely lose the siphon. Anotehr means of removing
accumulated is to attach a venturi on a small

The diff in the rate of CO2 use with and without a sump
might be related to the degree of efficiency of CO2 use
generally. The hypothesis being that the less efficient
your system is to start with, the less of a diff changing
to a sump will make. As a rough and ready hypothesis,
that's workable but leaves a lot to be desired. I think the
one above is probably better.

I can confirm that CO2 use is somewhat sensitive to the
water flow rate when hou have a sump. The flow rate seemed
relatively inconsequential when I was using a canister
filter -- first an Ehiem 2250 with the stock pump and later
the same filter modified to use an Eheim 1060.

CO2 is cheap and the benefits of a sump are several. It's a
matter of choice. A sump won't ruin your CO2 use, but it
probably will have an impact, perhaps a significant one.

I think all of this is consistent with George's data.
Hope that helps clear things up a bit -- there isn't much
more than such anecdotal data about sumps and CO2. I say
"anecdotal" because the info is based on only a few
aquariums and set-ups.

Scott H.
--- william ruyle <inquartata at comcast_net> wrote:
> Scott, by your glee I surmise this is not a good thing:-)
> However, and I may have an imperfect understanding
> of how George Booth does CO2 injection: the sump has
> a lid on it where he injects the CO2, preventing loss.
> The
> sump in question is part of a wet/dry system, right? If
> not,
> please excuse my misinformed post--I sometimes get into
> trouble when I don't go upstream on the thread:-/
> Bill
> > He he. It also helps you move a lot of CO2 out of the
> tank
> > ;-)
> >
> > sh
> > --- billw at waveform_net wrote:
> > > . . .Using a sump
> > > will let you move all your electronic gizmos out of
> your
> > > tank, and the
> > > sump will help keep the water level in the tank
> constant
> > > as well.
> >

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