Just picking up on a couple of questions/issues since I last posted.
Spectrum is as important if not moreso than intensity. Red-leaf plants need more red light than green-leaf plants. The colour of the leaves is due to the light colour that is being reflected off the leaf. This is one reason why plants do not need green light, only red and blue--they reflect green. In the case of red-leaf plants, more intense light is needed to compensate, otherwise the leaf will tend to be less red and more olive green/red or brownish/red, depending upon plant species. Having blue-heightened lights over the tank as you have is not going to help a red-leaf plant. And therefore, providing the proper spectrum will allow you to reduce the intensity.
Watts per gallon really means little as there are so many factors plus the type of light--T8 for instance is more intense than T12 in identical sized tubes of identical spectrum and identical watts. And some manufacturers make tubes with more intensity and less wattage (to save energy), so a 32w can be equal to a 40w of the same spectrum/type.
As for red tiger lotus, I have this plant in my 29g and 33g tanks (one in each) under one Life-Glo tube (6700K). The 29g tube is 20w, the 33g is 25w, and the plants are growing fine for me though I know I could increase the light and get brighter red. Flowering in an aquarium is, according to Kasselmann, very rare. And the flowers only open at night (in darkness).
There is a balance in all this. Light must be adequate in spectrum and intensity to begin with, and then nutrients must be in balance with that. If anything is missing, the plants will slow their growth, and in extreme cases may die off. You big issue is the light, as I think I have explained, but if not please ask and I will elaborate.
Second though is the lack of nutrients. Without adding fertilizers the plants are struggling. They cannot make use of the light, which is why algae and/or cyanobacteria appears. These organisms do not care about the type of light. Algae will flourish in very blue light, in which plants would not even last [I'm talking total blue, just to be clear]. In mixed light that is not balanced, plants can make use of it and algae/cyano will. You obviously have high organics from the fish, fish food, source water--otherwise cyano would not be so bad. But something is bound to be missing. Plants need 17 nutrients, and while some occur in tap water (if it is hard), some in fish foods, and some from organics (decomposing waste, etc), some are certain to be missing.
Byron.