It will work to a certain degree...
I had been thinking about buying a new light fixture for the 75 gl. I have wanted to add red plants, but I knew I would need higher lighting. The sales clerk at BA's showed me to the Current Satellite Freshwater LED 48-60". The rating on this is 30W ,2000L, 6500K white & 48 RGB full spectrum. The clerk assured me this will be enough light to add the higher light requirement plants.
With this being my first LED purchase I want to know if this is really enough light for my 21" deep 75 gl. tank.
I have that light fixture and used it for a few months on my 90 Gal 24" deep low tech planted tank. I was able to grow several red plants. They grew slowly and the reds were not as intense as I wanted.
I replaced the Current LED fixture with a DIY LED build using 3 Watt LEDs - 18 x Cree Cool white, 18 x Cree Warm White, 6 x Cree Royal Blue, 10 x Ocean Coral White (1 x Blue, Turquoise, Red LED on each OCW module). Each LED colour was wired to a different driver and dimmer channel so I can adjust the spectrum as desired. I also added CO2 at the same time.
With the new fixture, the red colouring on the plants has exploded. Some of the colour change is due to the additional red spectrum provided by the LEDs used however, the colouration has become much more intense since the new light was added.
The DIY fixture cost about 3 x the price of a Current USE 48-60" fixture - mostly because I used a high-end heatsink and a dimming controller that can control 16 channels on LEDs and provide sunrise, sunset, cloud/storm/lightning and moon phase functions.
I do use a Current USA 18" fixture on a nano shrimp tank and it is perfect for that purpose.