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Re: Flat Cryptocorynes and nitrate removal

Roxanne Bittman wrote, Friday, Oct. 3:

>OK, so noone wanted to take a crack at my "flat cryptocoryne" question.....

OK, I'll take a crack at it.  From your previous description, you had four
fluorescents on a 20 gallon tank.  That is fairly bright light.  My guess
is that your crypts were single plants, planted a good distance apart from
each other, and that they were in an open, well-lit area with no other
plants shading them.  By "flat", I assume you mean that their leaves were
all pretty much horizontal.  If my guesses are true, the open, uncrouded
location of the plants is responsible, rather than the color balance of the
lighting.  If you wait long enough, the crypts will send out runners and
crowd themselves, and then you will get leaves pointing upwards.  Crypts
always look more decorative when planted in close bunches.  Given time,
good mineral nutrition, and CO2, widely set apart crypts will produce
enough new plants from runners to form decoratove bunches.

Re Plenums and excess nitrate:

I am still not completely sure just what a plenum is, but I gather it is
something like an anoxic zone in the substrate, and that one value of such
a zone is that excess nitrate could be removed there by the process of
bacterial denitrification, which reduces the nitrate to N2, atomspheric

I never have had a problem with excess nitrate, but I once did some
experiments where I put a layer of oatmeal flakes on the bottom of a 4 inch
diameter fingerbowl and then covered the flakes with an inch of medium
aquarium gravel.  I did this to see if it would be a good source of CO2.  I
put the fingerbowl in a tank, and it bubbled nicely for several weeks, but
it appeared that there wasn't very much CO2 in the bubbles.  I assumed that
the bubbles were mostly N2, since I couldn't think of anything else they
could be except possibly methane.  While disappointing as a CO2 source,
such a setup might function as a good nitrate remover.  It did not cloud
the water, and I did not see any evidence that the level of oxygen in the
water was lowered enough to cause any distress to the invertebrates in the
tank (which had no fish).

If you are interested, I would recommend cautious experimentation with this
setup---that is not too big a bowl.  You can vary the amount of oatmeal and
the depth of gravel over it. You could test to see if the gas were methane
by collecting some and seeing if it burns.   If you see distress in any of
your fish, you can always pull out the bowl immediately.

Paul Krombholz in Jackson, Mississippi with typical dry, warm, October