i don't overdrive my 4x54w t5's/icecap indv. reflectors. i could add one or two more but like the open space. i'd rather switch to 4x80w 60"t5's. as is i'm hoping my two crocea's situated ≤6" from the waterline can keep their colors longterm.
you didn't say how long your crocea's have been in your system, also what depth (i don't know a 75's measurements), and have you noticed color shift and or lose over time?