I used to have those kind of snails also. I believed they were sundial and removed them all. I never had any turbo snails and those little ones multiplied like crazy. I reason I started removing them is because they were irritating my zoas. They would stay closed and I used to find them at the base of the zoas. That is just my 2cents and could be wrong. Good luck on your decision and just keep an eye on them I suggest.