Hi, I have the same light albeit the smaller 600 connect. I have listed my settings below. My Duncan’s love this as does the toadstool, shed twice under this light and it’s only been on the tank 5 weeks or so!! Bear in mind placement and water quality also plays its part but by the looks of you tank you have that nailed! What are you dosing ??
Light settings( adjust times to suit but wouldn’t exceed 10 hrs max 12hrs a day)
Sunrise 6:00-7:00 = W 2%, B 2% , R 2%
Morning 7:00-9:00= W 30%, B 50%, R 30%
Daylight 9:00-15:00= W 65%, B 80%, R 40%
Early Evening 15:00-19:00= W 40%, B 65%, R 20%
Moonlight 19:00-21:30= W 0%, B 20%, R 0%
Give this a go and see how you get on. By the way...nice tank.