Some plants develop red growth when they are exposed to too much light, as an adaptation / defense mechanism. I have seen this with many "above water" plants, mostly ivy... Where the leaves that grow in direct sunlight grow red or almost purple, and the leaves that grow in the shade grow green.
As long as it's alive, red, growing and not turning yellow or brown (and not an algae), you should be all set.
I believe I have the same grass as you have in that last picture - it came with some latin name hydra... something (two words) (I kick myself for throwing away the tag). The one I got in the store almost immediately died off to about 1/4 the size. Now it is re-growing.
Some plants need to grow new leaves to suit new lighting conditions. For example, they will grow leaves suited for high levels of light, but under low light conditions those leaves will die, and they will re-grow new leaves that are better suited for lower light conditions. This is what happened with my grass plant - and has happened with many of my "Above water" plants that I transition from being out-door plants to indoor plants when we switch from summer to fall in Maine (they initially wilt, and die, but re-grow leaves adapted to the much lower indoor lighting conditions)
The store had much higher wattage than my 1.5 watt per gallon tank. The original leaves died off, and new leaves better adapted to lower lighting conditions are taking their place.
Lower light conditioned leaves may turn purple or red when exposed to higher levels of light. Newer leaves that grow from the plant should be well adapted to your new lighting system.
this following pic is the plant in question. 
