Why red plants aren't red, always turned into green?

After failing to keep the Ludwigia in my tank, there are many questions floating in my mind. Did alot of searching on internet to know how to plant it and why it happened. Many forumers also complain about the red aqua plant that it is kind of difficult to keep, always turning green from red, no matter how much irons added into the tank. Actually the main reason is that different light demands from the red plant and the green plant, therefore when most of the green plant grows healthily, the red plant always turned into green. Thus confirming that both plant's light innate nature demand are different.

Green leaf absorbs red and blue light in spectrum and red leaf needs blue and green light, this is because red plant has anthocyanin in the leaf. They are actually reproached outside the B chlorophyll; therefore the red plants looked red. If you place the red leaf in hot water, the anthocyanin will then be able to dissolve in hot water, causing red color turning into green.

The secret of how to make the red color plant look gorgeous:
1. Extend the illumination period,
2. Increase the light intensity and carbon dioxide densities,
3. Make sure water is in low PH value and low temperature.If the above conditions are obtainable, then planting a red plant is not actually that difficult.

Regardless of green or red plants, both has iron in it, but is only in a micro substance (standard content is approximately 0.076ppm). Iron is important to many kind of enzymes, in the aqua plant, it is extremely important to oxidation reduction catalyst, like the carbohydrates oxidized nitric acid and sulfate return to original state, it has the close relationship with the iron.

On the other hand, oxygen produced during photosynthes is also depends on the iron albuminate-the organic compound, when lacked of iron, plants will then go into etiolation stage, and if condition worsen it may cause the plant to necrosis. Ferrous iron ion (Fe2+) is the most valuable ion in aqua plants, when the water chemistry changed from neutral to alkaline (i.e. when the PH value was equal to 7 or above), the iron can precipitate and becomes non-dissolved iron, this is the reason why PH value is preferred at the low level. Thus, from the above theory, no matter red or green plants, Iron (Fe) is an indispensable trace element.