It has a one inch inner diameter. Screens work fine for snails, however in a refugium they work even better on caulerpa. Catch 22 clog it with caulerpa and have a flood or clog it with a snail and have a flood. I will figure something out to stop this from happening again. Snails happen a lot less often, but in the house it would be a disaster. I didn't even realize the little bugger was in there. It could have been a hermit also. All I know for sure is I took out a black turbo shell.
No offense taken Kaiser, in fact you have me thinking again........... :shock: