You can try this purpose made tool for large scale removal - the 3-spike rasp end removes them and crushes the whole snail, rather than just the tubes - which grow back. The other end has a hook and blade for sniping individuals. Takes perserverence, and its hard to completely eradicate them since they tend to get into your pipes and other areas you can't access. https://reefeco.com/products/reeftool

