It doesn't look like BBA, no tufts.
It isn't diatoms - it doesn't come off.
It is almost red - it is like the plants are rusting!
Help! What the heck is it?
55g, 132w t8's, pressurized co2 at 1bps, dosed 1x a week with CSM+b and nitrates/potassium/sodium, water changes 30-40% every 7-10 days
