"spiral_72" wrote in message
ps.com...

I broke up 2 multivitamins and used them as soil fertilizers under the
plants. I used a slight amount of vinegar (instead of chemicals) to
bring the pH to 7.0

Vinegar *is* a chemical. Tinkering with the pH balance by adding
acids is a bad idea because you end up with an ion balance that is
very unnatural. The correct way to adjust pH is via buffers, that is,
you increase carbonate hardness to incrase the pH, or remove
carbonate hardness (by mixing with RO water) to reduce the pH.
If you are using CO2, the combination of carbonate hardness and
CO2 is what determines your pH.

What in this combination has rewarded me with slime algae and white
fuzzy stuff?

I suspect that tinkering with the pH by adding acid was one contributing
factor.

I've never had any of this before. The fuzzy stuff is
supposedly from decayed material... from where?

The fuzzy stuff is a fungus. Not good -- in a balanced tank,
you won't have fungus. Do a fifty percent water change to start
with, removing as much of the fungus and the blue-green algae as
possible. Then do a five-day blackout on the tank. Wrap it with
thick black plastic or blankets and put something over the top to
keep out all light. (Turn off CO2 during that time and stop fertilizing.)
If you are worried about O2 supply (probably not an issue with your low
fish load), stick an air stone in the tank for the duration.

At the end of the blackout, do another 50% water change and remove
as much of the dead algae and any other decaying material as possible.
Stop tinkering with the pH by adding chemicals. In fact, the pH value
is largely irrelevant anyway. Your fish an plants will do well at just
about any pH. Instead, get a nitrate and a phosphate test kit, and a
test of KH. For a low-light tank, keep your nitrates around 5-10ppm
and your phosphates around 0.5ppm, and inject CO2 to 20-30ppm.
For a low-light tank, don't worry about the CO2.

I suggest you search this group for articles by Tom Barr -- he's written
a lot of excellent articles on this topic.

Cheers,

Michi.

--
Michi Henning Ph: +61 4 1118-2700
ZeroC, Inc. http://www.zeroc.com