Encouraging Red Growth

[Ed Dumas <eldumas at telus_net>]

I have heard this thread here before, so excuse me for bringing it up 
again, as I cannot remember what the consensus was, and I did not have 
much luck looking it up in the archives. I am looking for some 
suggestions of things to do which might help encourage plants to grow red.

I know that red plants vary, because of conditions, in their colour. 
Does anyone have suggestions to help my plants grow more red than green.

I have a high light tank, about 3 watts per gallon, CO2 fed, with the 
following parameters:

kH 4
gH 8
pH 6.6
Nitrates 5 - 10 ppm
NH4 0
Iron .1 ppm
Calcium 20 ppm
Phosphates .25 ppm

Growth is good, algae is minimal. Some plants just tend to lose their 
redness, and move towards green. Any ideas out there?

Thanks so much.

Ed Dumas