I am no expert but from what I've personally experienced is you're have a nutrient deficiency. With that much light you need to do a solid EI dosing. The thread alage sometimes comes from plants leaching out nutrients when they are dying.From the Marineland manual, it's shows a PAR
Value of [email protected] a 12" distance,same as in my
setup, my ground cover HC grows well up against
The front glass,but is yellowing towards the center.
I also am starting to have thread algae problems in
that area.I'm going to back the fixture off 2", and see if it helps.
You didn't say what your substrate was. Is it inert? Ecoplus?