I'll add this here
i've done two doses of this, once before my water change, and once after. i've been dosing excel because my co2 distributer's compressor was down and i was without co2 for 2 weeks. needles to say, i got some hair and black algae on some leaves. i was lss concerned with black as it just needed to be trimmed off. the rotala looked pitiful and i didn't want to thrash that plant.
i missed a few spots of the black algaes when i did my water change this past time. tuesday was water day so i performed my trimmings, changed my filter pads after stirring up all the muck i could, chagned 80% water. added ferts, 3 ml of the tetra algaecide. and my co2 is back up and running. i continued my dosage of excel which was 5ml. lights were turned back to full on, instead of half (4 bulb fixture)
by thursday the few strands of black algae in the tank were red. TO MY UTTER SURPRISE. i'd love to get some samples to sewingalot. under bleach this stuff turns green. but its dead and red, and brittle at this point and rubs of with my fingernail now.
oh and my hair algae went POOF.. rotala is making a sharp recovery with lights and co2 back to where they should be