I have a 55 gal planted tank with 7 wisteria plants and three java ferns growing in it. th wisteria were doing fine until a few days ago the lower leaves are starting to turn brown. they are not dead yet but don't look so hot but the top of the plant is looking great. is it a light problem? top leaves blocking lower leaves? the java fern are doing fine and are actually starting to sprout new growth. i have no Co2 injector as i was hoping my fish would provide the co2. does this work? they are tiny blue spotted and banded sunfish. i have nine of them. Nay input would be great.