Hmm. This has been an interesting thread, Is it BBA season?
I checked my KH last night and readjusted my CO2 to pump about 40-50ppm of CO2 into the tank -- that's with a KH of 5 and a shifting pH of 6.3 (off) -6.5(on) -- on my Milwaukee controller. My "off" setup used to be 6.5.
I might pick up a 500ml bottle of Excel from online while I'm ordering a few other goods tonight. Since my nutrients seem to be in check and I am dosing EI style, I might also try dosing Excel at the recommended dose first. My algae isn't bad, but there's been enough to raise a flag. Better to nip it in the bud before it gains a greater foothold.