Perhaps I have had success has to do with my limited plant selection.
My lights are under 2 wpg and I finally bought only plants that
accept that condition. If those not getting a fix are using high
light and/or co2 maybe that has something to do with the failures.

Hey, count yourself lucky. There are around 200 species of fresh water Red
Algae so you may not have the same stuff others have. If you have any doubt
about how nasty and tenacious this stuff can be, just do a search for BBA
ALGAE or look at the following link:

http://www.thekrib.com/Plants/Algae/bleach.html

Chris.