Hi Hoppy,
Well, your point is related to a question that I've asked before....what is the value of more light. Plants are growing well in my current 84g with 2x54 T5HO. Co2 saturation is good and I fertilize daily with the full regimen of Pfertz products.
So what would be the benefit of more light. I've assumed my light to be moderate. I did try one plant that didn't do well...forget the variety...but even for current plants - Red Temple, Combamba Furcata, would they benefit from more. By benefit, I don't necessarily mean grow faster, but fuller, more colorful, less leggy over time...those kinds of benefits.
I've read others here go with 3, or 4 bulb fixtures. I assume there is a benefit other than excessive growth.
One of the things I like about this particular fixture is that the reflectors are individual and look deep. I would like to reduce light spillover from my stock Hagen fixture. I'd like to get some sparkle into the tank. The Giesmann Midday and Aqua Flora have acclerated growth and brought out more color in plants and fish, but have lost some of the sparkle of the original bulbs...so having more variety of light seems like it might be a benefit.
As for cost, I don't like to waste money, but when it comes to one-time expenses I'd rather spend and be satisfied than save money now and wind up upgrading again.
So what do you think? What would more light accomplish OTHER than faster growth and potential algae problems

And if there are benefits, how mch more light do you tihnk it would require to provide those benefits.
Thanks,
AB