I have some of these snails as well and I think they are collonista snails. I have not have problems with them yet and they have travelled trough 3 systems. They are vegetarian snails. If you Google it you will see the same pattern as yours pop up a few times. Hope this helps, @RiaanP helped me with the same snail id, he is a walking encyclopaedia.. here is a link I found. Collonista Snail | Melev's Reef
Hi, thank you for the feedback so far. @RiaanP, I am not sure. My suspicion is from snail eggs on zoas I bought. I have an outbreak of tiny snails like this. Must've been hitchihking as I have not had this type of snail before, now 100's.