Not brand new to the hobby. Been absent for about 10 years. It is my understanding that most snail killer remedies contain copper. The impact of snail killer on the fish and plants I want to keep is not relevant here. No fish, and these plants I don't mind throwing away. Just the impact on the filter media. Made the mistake of adding a few cheap Elodea Densa to a newly cycling tank, just so there was a bit of green in there. I could either just bin the plants, or move the plants out and treat the plants separately. I'm still left with the possibility of snail eggs though in the tank. I've already spotted a good few snail eggs.