I agree that your lighting most likely isn't enough. I would stay away from the orbit marine led as it's gonna be very similar to what you already have. Your nitrates are good but the phosphates are to hard to tell. 0.0-0.25 is way to wide of a range for phosphates. 0.00 is way to low and 0.25 is pretty high. Target range for phosphate would be 0.03-0.05 little higher isn't too bad.I also re-verified the reading following a water change...
Phosphates - 0.0 - 0.25
Nitrates - 0-5 ppm
Now I've also moved the BTA to 1/2 way up the water depth ( from 2/3 to 3/4 deep previously) in hopes that slightly more light will be beneficial.
I'm doing a ton of lighting comparison. I'm leaning toward the thought that I don't have strong enough lights.. I'm looking at replacing my 27W led's (Fluval Aquasky LED) with
CURRENT USA ORBIT MARINE LED AQUARIUM FIXTURE 36"-48" - 35W.
If you have any suggestions for lighting that is better in the $200 and under per fixture please let me know.
For 140$ with WiFi these are pretty nice. http://m.ebay.com/itm/201332405274
If you don't care for the WiFi
http://m.ebay.com/itm/281553749262