With that much light you also need to be dosing liquid carbon along with the CO2 as that CO2 system will not be enough for that much light. You can buy Metricide 14 Day Solution, a gallon for about $27 shipped. Mix it at a 1:1 ratio with RO or distilled water. I mix it up and use old Excel bottles. It has to be kept in opaque bottles as light breaks the Glut down. Then you want to use it at a rate of 1ml Glut (Metricide14) for every 2 gallons of tank water. In a couple weeks time you will probably need to up your dose it 1ml Glut to every 1 gallon of tank water along with using the CO2 system. You also need to be using dry ferts so plants get all the macro and micro nutrients they need. Here is the info... As for dry fert this $15 package is all you need and will last a couple years...
http://greenleafaquariums.com/aquarium-fertilizers-supplements/micro-macro-fertilizers.html. You need 3 dosing bottles found at the bottom of this page...
http://greenleafaquariums.com/aquarium-fertilizer.html. This is a good thread about dosing PPS-Pro. Only read the opening post not all the comments after it....
http://www.aquaticplantcentral.com/forumapc/pps-analysis-feedback/39491-newbie-guide-pps-pro.html. There are two things I do different from the article. First I use 3 dosing bottles as I split the macro nutrients for better custom dosing to the needs of the tank. Nitrates in one bottle, phosphates and potassium in one bottle, and micro's in the 3rd bottle. The other thing you'll notice the recipe calls for using MgSO4, magnesium sulfate, which you don't need if you have hard tap with a gh of 4 or above. The plant you have does appear to be red nesaea since it has pink red stems. It is a high light plant that needs CO2 and dry ferts. You also need to plant each stem individually so leaves of each stem almost touch the leaves of the stem plants around them.
and your opinions are what's driving my tank hopefully towards a healthy vibrant joy for me..
