Anyone out there know of a type of algae that does not die by excel nor h2o2, I removed all my wood yesterday, removed as much of this tough filament algae as I could by hand and direct dosed the algae with full strength excel let sit 15 min, rinsed and then did h2o2 directly after, as well as letting it sit 15 min, looked today and this crap is just laughing at me [emoji23][emoji23].