All of my plants seem to be healthy and growing rapidly (at least the
fast-growing ones), except for one. Right now I'm not too concerned about
that one. I posted about "brown-hair algae" a couple of weeks ago. It is
still there, and spreading I think, but very slowly. I have had what I
believe is BBA starting about the time of that post.

I have read a lot on the web about this. I can't really find a way to deal
with it though. I know hair/brush algae is tough.

I am changing 20g water every 4-5 days. I have to use RO water so I add
Kent RO Right plus one quarter tsp MgSO4 to the water I put in. Could the
lack of Calcium (or something else) be the problem?

pH 6.6
KH 3 (this is color-change after 3 drops, NOT before, is that the
correct way to read it?)
Presumably CO2 ~20ppm
Using TMG as directed, except I break it down into the correct amount to
dose twice a week.
110w/55g

I know you want to limit PO4 to control algae, but since I am using RO
water, and no PO4, could this be a problem?

Would it help to rip out the most-affected plants? I gather not, from what
I've read. But I have visions of a thiving black algae tank. Am I
over-reacting? Is this a phase after adding bright lighting (6 weeks ago
with the plants)?

I am also getting moderate pearling, which indicates to me that the plants
are healthy and growing, but the algae is pearling too.

One other thing, NO3 is going down (not just after water changes), when it
gets 5ppm I add one quarter tsp KNO3 which brings it back up to 10ppm.

Also I've read about blacking out the tank.

I can provide more info, but I've probably tired you out by now.

thanks so much,

bob allred