Unknown Algae on Mini Fissidens. HELP!

[ken90ken]

Hi, i've noticed this white cottony thing growing on my mini fissidens. Anyone here able to ID it? I also recently bought 5 horned nerite snails to help with this issue but they've only been eating this white cottony thing on the glass and not the mosses.

This is a 2.5g CRS tank in my office, i'm using RO/DI water + Mosura Mineral Plus and a half dose of Excel.

I know that plants require a variety of nutrients, so my other question is, do i have to buy nutrients? (e.g. Flourish) If so what should i get?

Thanks for the help!

[ken90ken]

I just realized i posted in wrong section i think, sorry mods, please move this thread if you think it is inappropriate.