You could raise KH a bit higher. Mine is up at 6.5 or so.
PO4 looks quite high to me. I try to target 0.5ppm. Some say that PO4 is the best algae-limiting-factor. So I think your best bet is to cut this way back when dosing.
Nitrate also looks high, I target 10ppm.
I don't like those goofy CO2 ladders. By far the most efficient way to disolve a gas into a liquid is with vigorous churning (though not at the water surface, that will make it all evaporate again). Perhaps try putting the CO2 output tube directly under the filter intake tube. The bubbles will then get churned up by the impeller. As long as there's no splashing of the water back into the tank, it should work. An even better alternative is to make a powerhead reactor. There are several web sites detailing how to make these, here's one: http://www.csd.net/~cgadd/aqua/diy_reactor.htm
Probably CO2 is not the issue though, so I don't know how far you want to go with that...
It might pay to go ahead and do that 3-4 day blackout to wipe out the algae and then sort of start over, dosing less PO4 and nitrate.
Keep us posted, I'm rooting for you. Don't let those lower life-forms keep you down.
PS. Another algae controlling technique that many people use is have a break in the photoperiod every day. Perhaps try lights on 5 hours, off 2 hours, on 5 hours, off 12 hours. They say that algae takes longer to start photosynthesizing than plants do, so the algae will have less productive time if the light cycle is interruped in the middle of the day.