Honestly I'm not sure if this is 100%, but I believe they'll be fine. I know that all plants feed off of ammonia, but I'm not totally sure what 6 ppm will do. I don't think it's enough to kill it though, so IMO it should be fine.I accidently dosed my tank to 6 ppm. (Fishless cycling overdose) I left my java moss in there, will it be okay?