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Re: Night Time Aeration / O2 Kits

Mark Robinson asks "Also, if I buy a dissolved oxygen test kit, what are
the ideal levels I should shoot for at night and in the morning."

As I've mentioned before, we have a heavily planted and heavily stocked
135-gal tank (with pressurized CO2). Many months ago I removed the solenoid
and was very happy with 24-hr CO2. As our angelfish got larger, the morning
O2 level began to drop to the point were the fish were sometimes in
trouble. Nighttime airstones solved the problem, with thriving fish (it
also lowered our max. CO2 level and taught us that we didnt't need 20-25
ppm at all -- 12 ppm is working just as well and are barclaya leaves are
without holes for the first time!

The Tetra O2 kit is cheap and good enough to know if you are in trouble. As
usual, you have the difficulty of comparing your water test sample to a
paper chart. The LaMotte Dissolved Oxygen kit 5860 is very precise (and I
would bet accurate) but not cheap. It's a titration test that lets you
easily measure to 0.1 ppm units. LaMotte Kit 7414 is the almost identical,
but has a powder reagent, sulfamic acid, that is a bit harder to manage and
less in quantity than kit 5860, which has a liquid, sulfuric acid, that
will last for more tests.

Different fish species can tollerate different min. O2 levels. The
following is from the LaMotte instruction booklet:

 5-6 ppm = Sufficient for most species
 < 3 ppm = Stressful to most aquatic species
 < 2 ppm = Fatal to most species

By the end of the day we have always had supersaturation, with about > 9
ppm O2 (pearling starts at about the saturation point which if I remember
is about 8 ppm for water at 80F). Now, in the a.m. with the two airstones,
I measure about 5.5 ppm. 


Jared Weinberger                    jweinberger at knology_net  
______    http://www.knology.net/~jweinberger/     ________