Bookshelf stream II: battle of the algae (long)

Hello to everyone,

not long ago I asked for advice (and got very good replies :-) ) about my
project of putting a small "stream" aquarium on my bookshelf.
Since then the thing has taken shape, and here is how it looks like now:
http://grisu.no-ip.com/acquario/book...bookshelf1.jpg
The yellow scarf hides lights (2x11w), electric wires, DIY sugar-yeast CO2
bottle, and the DIY filter, as shown in this pictu
http://grisu.no-ip.com/acquario/book...bookshelf2.jpg
The pump is covered by a "chef hat" made gluing together strips of aquarium
sponge. It pushes the water along a pipe hidden under the gravel which then
rises above the aquarium and enters the filter (simply a plastic container
filled with ceramic elements). From there the water returns into the tank.
I intended to hide pump, heater, and CO2 outlet behind a thick and tall
plant, and here comes a funny story. To this pourpose I planned to use
heterantera zosterifolia (the tank should be an amazonic biotope, cfr.
http://fish.mongabay.com/biotope_amazon_blackwater.htm). So, my wife went
to the local fish shop, and the shopkeeper sold her a plant supposedly
"belonging to the same family, just about the same that you asked". It
turns out to be alternanthera roseafolia! Somebody judges plant affinities
by the sound of their names!!!
Happily the alternanthera seems to do the cover job quite well, and it is
growing steadily.
http://grisu.no-ip.com/acquario/book...bookshelf3.jpg
The other plants in the tank are echinodorus tenellus, which are sending out
many runners along the bottom. The dark gravel covers about 1 inch of
fertilizing soil.
About 10 days ago, when nitrites went down to 0, I put 10 neon tetras. As I
was told, the current generated by the 90 g/h pump isn't too strong for
them, and they are doing just fine. As soon as I'll find a shop which
carries them, I'll put in 3-4 otocinclus, as well. Right now in the tank I
have:
Ph 7.5
Kh 6 degrees
Gh 8 degrees
Temp 25 C
No2 not measurable
No3 25 ppm
Lights are on 10 h/day.

And now comes the problem. The pieces of (boiled) wood in the tank right
from the start have developed a white furry stuff on them, which later
appeared also over the most well-lit areas of the gravel:
http://grisu.no-ip.com/acquario/book...bookshelf4.jpg
Until now I didn't worry too much, thinking that the white stuff would
disappear as the tank ages. And so it seems to be... except that as it goes
away it is being replaced by green slimy stuff, which is also finding its
way over some echinodorus leaves. And that worries me a lot.
http://grisu.no-ip.com/acquario/book...bookshelf5.jpg
Has anyone some good advice on what to do about this, or, at least, can give
a precise name to these unwelcome guests of my aquarium?

Thanks a lot,

FP