wont work. it will probably just kill subwassertang. it does not anker its self in any way to anything its just a free floating plant. and when you glue get the GEL type. it will make your life soooooo much easier. i just glued down some java ferns to some rocks and i have used it on drift wood too. im not quite sure how doing it under the water would work cause water cures the glue almost instantly. i pull what ever i want to glue to out, wipe it off a bit and apply glue and plant let it sit about 30 seconds and back in the tank it goes.