Re: Re:Trickle Filters and CO2 Loss

["Adam Shaw" <adams1 at comcen_com.au>]

>From: "George Booth";
>> I have read the article on aquatic concepts regarding co2 loss from
>> trickle filter systems, and really it has left me wondering.
>Bummer. That was not the intent.

Sorry George, I did not mean that the article was not well written,
confusing or that the content within was not clear. One part I had been
wondering about was that the data collected spanned only a smaller
period of time, over which the concentrations steadily decreased - There
seemed to be no point at which some form of equilibrium emerged (within
a few ppm of a mean value or similar). It just kept falling... I realize
that daily the concentrations would fluctuate - it just concerned me
when the data started at a high concentration and then over the period
of the data acquisition the concentrations steadily decreased. I may
have misinterpreted however and sorry if I have done so.

So far I have a tight fitting lid for the bio-media chamber on my unit,
and a bulkhead delivers the water to the drip tray through the tight
fitting lid - so basically the media chamber compartment is a sealed
unit. There are also tight fitting lids for the other half of the sump,
and the return pipes, power chords etc go through one half of the lids
(i.e. no large gaps or sections of open top for the unit at all). Will
that be sufficient to stop CO2 losses? Oh, and the return line is a
spray bar but submerged below the water surface - little surface
agitation.

I have kept wet/dry systems on reef tanks before, however this is the
first time I have used a drip tray (previously used spray arms), and the
top of the bio-media compartment had a 1 1/2" wide slot along the top to
allow air in (no forced pumping). The system worked remarkably well as
far as nitrite and waste assimilation goes. Obviously however, such a
system would cause dramatic co2 losses when adapted to FW planted. By
sealing the media compartment and not allowing air in through other
methods (i.e. pumping), wouldn't such a sealed system affect the ability
for the bacteria to function in the bio-media compartment? I would have
thought that even though the plants enrich the water with oxygen during
daylight hours, at night time they'd consume the oxygen and the bacteria
would have daily cycling of oxygen starvation, and then oxygen
enrichment, rather than forming a stable equilibrium (i.e. through
supplementation by either open top media chamber or pumping to make up
for the plants consuming oxygen and not producing). If this cycle
existed, therefore would not the bacteria colony go through a daily
die-off and then regeneration as the concentrations of part of their
'food supply' decrease, and then increase when the lights are on?

Thanks again!

Adam Shaw