Your Tank Lighting
You may have a couple of thin T5 high output lamps in that fixture. This much light over a 90 gallon tank is low light, but will be enough for the dark green, aquarium plants. Anubias, Java fern, Hornwort, Bananas, Anacharis, Pennywort and any of the mosses will be fine under this type of florescent lighting. The 6700K lamps are very close to natural daylight and the good thing about florescents is they last a long time.
"Fear not, my young apprentice. Just change the tank water."