trying blackout method

["Eric Wahlig" <ewahlig at earthlink_net>]

I have a 25 gal. tank that was running just fine for over a year and then I
decided to double the light intensity. Actually, I think I probably almost
tripled the light intensity going from two 24" T-12 FL running on a
magnetic ballast to four 24" T-8 FL that run on an electronic ballast.
Anyway, I saw immediate growth response in the plants but I was slack on
keeping track of the nutrient levels and I'm sure the tank ran out of
nitrate or phosphorus or both. The tank went sour and all kinds of algae
developed. I made a couple attempts at removing it but it had become very
well established and each time it over ran the tank before the plants could
recover. The plants are Java fern on wood and a small Crypt. species
growing in the substrate; not exactly fast growers but not as slow as some
other plants. So now I have an opportunity to try the blackout method for
algae control that I have been reading about.

I picked the bulk of the algae out of the Java fern and put these two
pieces of wood that are covered with the fern into a large Rubbermaid
storage container covered with a lid. I put a couple gallons of water in
the bottom so it will stay humid in the container. This will stay in the
dark for a week. I cleaned the algae out of the rooted plants as best I
could and also scrubbed the glass and the hang-on filter clean of algae and
turned off the CO2. I then did a 95% water change with our normal tap water
which is very soft and has a very low mineral content. The only mineral
present is calcium which the municipality adds to about 3 degrees GH.

The question I have concerns the water. As I understand it, the plants will
be in the dark for about a week so they will not be able to assimilate
nutrients. Therefore, I have put no nutrients back into the tank as I think
its just a waste. I'll do a large water change again when I end the
blackout and adjust the nutrient levels at that time. Does this sound like
the correct approach or should I supply the plants with all necessary
nutrients during the blackout week?    

--- Eric