I'm not 100 percent sure about this, but I believe the blue light is for salt water. I use 6500k light bulbs and they seem to be the standard for freshwater plants. The total wattage is nice but the 8w each isn't very powerful. They will grow plants though. Depending on how tall your tanks is will depend on how well they work. See if that manufacturer makes a fixture that comes with 6500k bulbs. I have a similar fixture as that except it has 4x24w bulbs and an really pleased with my plant growth.
Hope this helps!
Have a good one.