Could probably give it a good dose of excel. Stick it in a jar and try
Or stick it in several jars and try one with excel (or other glut product) and one without and see what happens
Staghorn will turn red when it dies off, and then shrimp will munch on it
Same for me, mosses don't have the cuticle layer that higher plants have, so are much more <"prone to damage by biocides">. This is also probably the reason why Vallisneria can be damaged, it is an <"obligate aquatic"> (a hydrophyte) and doesn't have a cuticle with stomata in it, but has a permeable epidermis, through which gases and nutrients diffuse.