I had a persistent light film (3 month old 55 SW
) and I skimmed, etc and levels were peachy but the film never left.
I brought home a batch of razor caleurpa, threw it in and viola.... the film was GONE! It is crystal clear on top now.
Yes I run 3 power heads and I was wondering about that film for a long time too, I have tons of water movement!
Film is still gone. The fish love the caleurpa and I am happy.
Weird. The tips of the caulerpa turned white for a sec then back to green, I think because it was absorbing the cause of the filmy stuff.