The GE light you sold me is great!
Concerning the algae though, a red flag that came up was your nutrient proportions. Time and time again I have read that this is the largest culprit, or most effective way to managing algae. The golden ratio between P:N is 1:10. right now you've got 1:100. Your K is in good order so that shouldn't be a factor.
I would try to lower the N levels some, to about 5 and raise the P to about 0.5.
Easier would be to add P until you get 1ppm and keep the N levels where they are. This move can be risky though b/c if there is too much P for your plants to process, than your tank will be algae heaven; however I've read about about Tom Barr keeping P levels at about 2! with phenomenal results. This is providing you have good CO2 and light levels so its your judgment.