Ok, first and foremost, dose Excel every day. The plants are lacking enough Carbon and the addition of the Excel will help imensely. Also, when you dose the Excel, use a pipette or other device and spot treat the algae. You have both BBA(Black Brush algae) and what appears to be slime algae and the Excel will kill both of them with spot treatments and regular dosing. Follow the instructions and you can rarely go wrong.
The lighting is plenty. No worries there. You can go with the 6500,10000 if you want but is not needed. No actinic of course.
Now for the hard part. Dosing. Here is what I dosed when I had Excel and within 3 weeks, the algae was gone and the plants thrived.
Sun, Tue, Thurs, dosed 10ppm KNO3, .88ppm KH2PO4, 20ppm K2SO4.
Mon, Wed, Fri, dosed .3ppm Iron from CSM+B
Every day but Saturday Dosed Excel at recommended dosage spot treating in the the beginning to kill BBA. Also double dosed after waer change.
Sunday after water change, 40ppm Calcium and 10ppm MgSO4.
No dosing Saturday
This is the EI method of dosing; Estimative Index and assumes that there will never be a shortage of any one nutrient which is the main cause for algae problems. DO NOT DOSE THIS UNLESS YOU ARE WILLING TO DO 50% WATER CHANGES WEEKLY! This dosing regiment requires it to prevent the levels of poisoning your fish.
I have a spreadsheet I specifically designed so a person can see how it works. If you want I will send it to you.
The only other thing I would say that will help immensely would be pressurized CO2. But even with it you need a regular dosing regiment so the plants outcompete the algae.
Root tabs are a must but put them directly under the roots of the large swords. Micro Swords are extremely hard to grow, period. More light, more nutrients and a nutrient substrate are almost required to grow them.
The only plant I see that might not be aquatic is the tall one in the middle with the wide leaves on narrow stems. Looks like an Amazon Sword but could be wrong. Click HERE
and take a look to see if you have any of them. I know you researched it but we all make mistakes and LFS will not tell you 9 times out of 10. I had hedge for 6 weeks before I found out.
and download the calculator for dosing. It is priceless for calculating the dosing and I have used it for hours and hours. You can stay with the dosing I put above or go with their numbers as far as recommended dosing. Just tweek it as needed if you see any signs of deficiancy. I would dose your iron at .3ppm however regardless of what you dose the others at. At that much light, the plants will use it extremely fast.
Please post any and all other questions. I asked hundreds of them before I finally got my plants to grow the way I wanted them too and I would do it again. It was the only way I finally found something I could use and get my plants to grow the way I wanted them to.