First planted tank - am i doing it right?

[mikeybabs]

Hi guys. Here's some info on my first planted
This is my lighting: 24" 2x24W Miro-4 T5 High-Output Retrofit Kit w/ Bulbs

It's a 55 gallon tank ... I'm using seachems fluorite black sand 2" as the substrate. It's moderate to heavily planted. I have the flourish line of fertilizers and been using excel and following seachems recommended dosing suggestion. Its been about 2 weeks now and the plants seem like they are doing good. Haven't noticed any grow yet but I've been told my plants are slow growers. My lights are on 4 hours on then off then on another 4 hours... (10:15am-2:15pm then 9:15pm-1:15am and repeat) Here's a picture of what my tank looks like: http://nobodysfat.com/plant.jpg

It has a fluval 305 and ac110 as filters. I guess what I'm wondering is... Are my lights considered high light? Can I grow these plants successfully without worrying about dosing and co2? What method should I research and what should I worry about most? I have not learned to test for co2 yet. Should I increase lighting duration? Is a gap in lighting ok? Thank you all