Re: No strings of O2 bubbles

>From: Calvin Chin <ad7437188 at v9001_ntu.ac.sg>
>Date: Thu, 04 Jan 1996 08:32:33 +0800
>Subject: No string of O2 bubbles.
>My planted aquarium has been in operation for a year but I've never observed
>any srting of 02 bubbles streaming from the plant. I've in fact achieved
>lush plant growth with MV readings in excess of 500.My tank setup is as
>        - 500 litre, trickle filter (overflow)
>        - 150 W metal Halide
>        - C02 injected. Continuous PH monitoring
>        - temp maintained at 28 degrees celsius, general hardness at 4
>degrees german hardness, carbonate hardness at 3dh
> My questions are:
>1.      Is this normal? I've been reading postings from this list and
>everyone seems to be achieving this phenomenon except me. Is it because my
>water has a slight current as there is a powerhead swirling inside my tank?
>Plant growth is normal and in fact my cabomba is growing well.
>2.      As my tank was converted from a marine setup, I had the chance to
>start everything anew with some equipment carried forward. Right now, my
>ozoniser and protein skimmer are idling. Can I use them in my feshwater
>plant setup? What does the 500 plus MV reading which would be unattainable
>for Marine Tanks mean for me?

If I did my math correctly, 500 liters is about 130 gallons.  Is the only
light a 150 watt metal halide lamp?  How many lumens does it produce?  I am
wondering if that is enough light for such a big tank.

Another important question is, What pH do you maintain?  If you are
maintaining it at above 7.0, then you may not be giving the plants as much
CO2 as they are capable of utilizing.  Try increasing the amount of CO2
injection.  Get the pH down to 6.8 or so and see if you don't get streams
of bubbles. I bet you will.  Be sure and tell us what happens.

I am guessing that the 500 plus mv reading is some kind of redox value, and
that 500 plus means that things are highly oxidized.  Am I right?  That is
probably normal in a tank with a good growth of plants.

Paul Krombholz                  Tougaloo College, Tougaloo, MS  39174