Still algae fighting...

Hi everybody,

a long story with many questions follows:

At first thanks to all who replied to my questions on how to fight algae
about 2 weeks ago by listserver or by email. The bottomline was: I have to see
that my plants outcompete the algae, that means optimum conditions for my
plants. I now read the standard book on optimum conditions, the
Dupla book "The Optimum Aquarium".

Here in Germany, you can also get a brochure by another company named 
Dennerle (kind of competitor to Dupla) with the title: 
Algae - no problem, we defeated them long ago. 

I compared the Dupla and Dennerle approach, according to *both*,
I made the following mistakes:

- not enough Fe in ground - beside some Tetra Crypto fertilizer tablets, 
   my ground/gravel has no laterite in it. 
   This prevents the plants from growing at their full
   potential. I plan to use some Duplarit (see question).
- not enough Fe in water (only 0.05 ppm) - although I use Duplaplant-24 daily. 
   0.1 ppm should be achieved. Therefore I plan to add Duplaplant tablets 
   starting with the next water changes.
   (I get yellow leaves on some plants, so I guess that I really don't have
   enough Fe.)
- too much surface movement - removes CO2 too fast. I adjusted to have a
   moderate surface movement. Both sources say that O2 should only be
   introduced by plants and not by surface movement/aeriation.

In the Dennerle brochure, some additional actions are described which I also
try to follow at the moment:

- light pause at noon - currently I have 5 hours of light in the morning,
   a break of 3.5 hours at noon and 5 hours of light in the afternoon. 
   Dupla states explicitly that this is nonsense. I do it anyway because 
   I think that it won't hurt- I hope... The plants are emitting fine bubbles
   after some hours of light, so I guess that they are achieving photosynthesis.
- light color - I bought a special Dennerle light with gaps in the spectrum
   to fight algae. Now I have this neon tube and a triton tube, both 15 W
   with aluminium reflectors. (I have a 30 gallon tank.) 
- In addition to reduce surface movement, Dennerle also states that O2 content
   should be really low in the morning, something like 2-3 ppm (although they
   use mg/l, I guess that's the same here). I currently still have about 6 mg/l 
   at 7 AM in the morning, I guess because the plants produce so much O2
   during the day.
- more CO2 - in the Dennerle brochure, there is a table that shows what 
   PH values you get by injecting a certain CO2 amount at a certain KH 
   at 25 Celsius. They state
   that 35 mg/l is ok, therefore PH 6.7 at 5 KH (that's what I have) should
   be desirable. I adjusted my PH controller to 6.8 because Dupla says
   6.9 is ok and I decided to go for a compromise. So CO2 should be about
   20-25 mg/l now. My neon tetras seems to like the low PH - for sure.
- discard leafs with algae - I do this periodically, although I wonder
   if my plants are growing them fast enough, especially the anubia.

I also introduced 4 small SAEs who are busy searching the plants for algae,
although I have the impression that they only eat young algae and not the 
older, longer "black" threads that I mostly have.

It did not really get better so far, but also not worse either.

Finally my questions:

1) Is there any sense to use Duplarit-K (I think that's the name of the red, 
   big balls to be introduced in the ground *after* the tank is already 
   running) without having heating coils in the ground?

2) What do you think of the light pause? Nonsense or useful?

3) What about the O2 content? Which value do you think should the water 
   have in the morning? Dennerle states that most tropical fish come from
   water with 1.5 to 3 mg/l anyway, Dupla seems to be a bit more careful. 
   Dennerle claims that algae thrive in an O2-rich environment/current,
   that's what I also see.

4) I read in the Dupla book that purple-colored light promotes algae growth.
   The triton looks purple, the Dennerle is more reddish. Dennerle claims
   that blue is the algae-promoting color that's why they have the gaps
   in the spectrum and the tube looks more reddish.
   Do I better replace the Triton
   with another Dennerle? The point is that the tank looks different already
   with one Dennerle tube, how will it look with two reddish tubes?
   What are your experiences with Triton & algae growth?
   BTW, Dupla discourages the mix of different light colors at all. Any
   comments on that?

Pls. feel free to give me your thoughts on all you read here, especially where
Dupla and Dennerle disagree.

Thanks a lot in advance, Andi from Munich, Germany.