In your own words you say that the HM makes up the bulk of your scape. Would you say it also exhibits the highest growth rate as well ?

The draw back to high light sytems is that in extreme cases we may very well define the limiting factor often Co2, or nutrient deficiency.

Plants are highly adaptive in contrast to other life forms and readily cope with their enviornment. what I mean to say is that just because they can does not neccessarily mean they should.

Generally speaking, the perk of EI is that nutrient potential is unlimited... "Within Reason"

Excessive lighting commonly throws everything out of kilter. 2.5 - 2.75 wpg. is plenty of light. Growth is more commonly limited by insufficient Co2 and no amount of light can alleviate that.

I would scale back the lighting first, observe and then perhaps readdress nutrient defficiency, but only one at a time to allow you to witness individual results.

I often refer to highlight deficiencies as "Shooting Star" syndrome. "The candle that burns the brightest, Burns out the quickest" ! Generally by establishing it's first deficiency, but even the finest livestock requires sufficient rest, and prudent handling.

My wife recently cut her lighting to half the original wattage, and doubled the growth rate in her tank. Gorgeous thick green growth too. Go Figger ?

F.T.R. that tank is a 50g. W/ 4-36w CF @ 6700k on a split 10/5 hour cycle...So your original lighting looks pretty good to me.