Re: O2 bubbles & CO2 measurement etc


Have you ever measured your O2 levels?  I too have tanks with UGF's that
have great plant growth (well, nothing like Karen's, but my cabomba grew
two inches last week & all had to be trimmed again), but with my current
55 gal tank I do not have O2 saturation during the day, since I run a
powerhead with the air valve open at night otherwise I kill fish!  During
the day the O2 stays above 5 mg/l even with the air off (presumeably because
the plants are producing O2), but if I turn the air on I lose too much CO2.
At night without the air on the O2 drops to aobut 2 ppm and has caused the
death of some fish :-(.  Live & learn.

Anyway ... what I'm getting at is, that if you don't have O2 at saturation
in your water then the O2 simply dissolves.  You only see bubbles when the
O2 is super-saturated & no more will dissolve in the water.


> ------------------------------
> From: Roger Crowther <lysander at crl_com>
> Date: Sun, 17 Sep 1995 19:03:30 -0700 (PDT)
> Subject: Re: CO2 Measurement etc
> I aim to change about 15% a week.  I add the Dupla tablets at this time.

Dupla & TOA suggest to change 30% once a week.  I think Karen changes 
something like 25-30% once a week.  I'd suggest you try changing more (I
know that will cost more in fertilizers :-() since you may be limiting
your plant growth by the build-up of alleochemicals inhibiting growth.
It seems to me like all your other conditions are prefect for good growth.

The other thing is, are you sure you're not getting growth & just not
noticing it?  I just removed a swordplant from one of my smaller tanks
& noticed it doubled in size in 3 months only after removing it.  I find
if I note how far from the surface certain plants are on a certain day
of the week then look at them in a weeks time, they certainly have grown
but I may not have noticed it day to day.  Stem plants seem to show the
most noticeable growth, especially cabomba & hygrophila for me.