Thanks everyone for all the recommendations and yes, I think the root cause of my hair algae was high light, and not enough co2. I got my cheap lux meter (LX1010B) that Hoppy was using and got an estimated conversion to PAR. Previously, I was putting out 60 par at the substrate in the center, now I'm at about 40 par. Measured dry, so I think its a bit more if its in water. Here is a breakdown of what I've been doing so far:
Less light duration, from 8 hours to 6 hours.
Less light output from estimated 60 par to 40 par.
Added 4 ottos.
Increased/stabilized co2, estimated 30ppm, or to the point fish are hanging out at surface, yellow drop checker, co2 on 2 hours before lights)
slight increase of EI dosing to get more phosphates.
replaced 90 degree elbow in CO2 reactor for more water circulation.
(I run an eheim 2213 on my 3.5 gallon tank, water moves in a CCW motion)
Water top off every other day.
Measured water parameters before weekly WC:
Hair Algae is no longer visible. Only trace is on the glass, seen sideways as slight green build up.
HC growth has significantly been reduced to more than 50%, evident by water tests before a WC, and less trimming. Prior, NO3 and PO4 would be severely low down to 10ppm and .5 ppm.
Blyxa used to be a stump with 3 leaves, now growing, and reddish, (indication of strong light?, really? at only 40 par)
Tank has signs of BBA, on S. Repens leaves, and used to be on drop checker.
Signs of what seems like GSA on older S. Repens leaves, and lower layer of HC, evident after a trim.
some blueish green fuzz like algae on rocks, nothing I've seen before.
Overall, I think the tank recovered well, however, the presence of other algae still tells me I have a long way to go, specially with CO2. I think I'm ready to buy a Parker H3 or H2 metering valve, my Clippard MNV4 requires daily micro turn increase, at a certain point, its just too much and requires closing and opening again. Does not work well with about 30psi working pressure.
Last but not least, pictures!
9/19/2014 Algae closeup