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Re: oxygen deficiency
> Date: Sun, 27 Aug 2000 08:16:37 -0400
> From: Jared Weinberger <jweinberger at knology_net>
>
> Chuck Gadd wrote:
> <<I think with fast plant growth (via CO2 injection, high
> lighting, and lots of plants), that the plants can supply more than enough
> O2 to make it thru the night without problems, even at high altitude.>>
>
> Not in our case. We have a heavily stocked, heavily planted 135 gal with
> commercial CO2 and PC lighting. In the afternoon we generally have nice
> pearling, which indicates (super)saturated O2 levels. This is confirmed by
> our LaMotte O2 kit, which sometimes shows a max of > 9 ppm O2. As our angel
> fish grew in size, the available oxygen was simply not enough to get the
> fish through the night -- a.m. O2 levels were sometimes dangerously low
> with the fish in distress.
I have to concur with Chuck. We are also at high altitude (5000 ft) and have
good fish-loads and CO2 and DO NOT have problems with O2. Back when we were
anal-retentive about testing, we would see 120% saturation at "lights out" and
90% saturation in the morning before the light came on. We also use trickle
filters so may be there is something to be said for that. But we also have good
water circulation. I think that if you have good water movement, you should not
see a problem with O2 over night. If you have tried to minimize water
circulation to avoid CO2 loss, you may have gone too far in that direction.
> I've seen an estimate that the bioload of an adult angelfish is equivalent
> to about that of ten cardinals. Looking at the sizes of our angels and
> cardinals, which are over one year old, I would guestimate it's at least 10
> to one.
One of our 100 gallon tanks has 4 full grown discus (each easily 3x the mass of
an adult angelfish) plus 40 cardinals. No problem with O2. Our 120 at one time
has 8 adult angelfish and a school of lemon tetras - no problem with O2.
Tell us about your water circulation.
George Booth in Ft. Collins, Colorado (booth at frii_com)
http://www.frii.com/~booth/AquaticConcepts