After a couple of years of watching and listening to snails crawl into the front of my MP20 and wearing out the propeller from rubbing against their shell, I decided to fix my problem. I decided to superglue mesh (the same clear mesh that I used for my tank lid which many of you have done also) to the front of the pump to keep them out. It's worked well so far with no problems. Just thought others might want to know.
