Ok; The first time I did the excell treatment I had my UV on the whole time and it the excell did very little to improve bba or any thing else for that matter.
So I decided to try it again without the UV, and I'm pleased to say that after 7 days it appears to be working. I'm gonna keep it up for 4-5 more days to see if it will be erradicated completely.
Observations after 7 days:There appears to be no new infected leaves. The previously black fuzz is turning almost white.
All along I've been pruning the the grossly infected leaves, The hairgrass got a major pruning as I suspect that it was trapping a lot of detritus which was contributing to the problem.I've also been keeping my ferts up and CO2 levels up, as always.
There is a couple of things that I did this last water change that seems to have had a very positive effect, and thats cleaning out both canister filters. I previously would only clean one out a time and I'd go months between cleanings.

I also vacuumed the crap out of the substrate and hairgrass. I suspect that rotting plant matter in the hairgrass and canisters were contributing heavily to this algae outbreak.(in hindsight......DUhhhh)
Heres one thing for sure, I'll be cleaning my canisters much more often and vacuuming the grass and substate at every water change from now on. I'll let you guys know what happens at the end of treatment and if the effects are lasting.
Marcel
__________________
FILSTAR Pimp #2
75 gal heavily planted,50/50 Black beauty,Eco-complete substrate, Pressurised CO2 with solenoid, ph controller, AB Reactor 1000, 330 watts 9325K GE PC lighting,Ehiem Liquidoser, 2-Filstar xp3 canisters.