Snail and hermit lifespans

[daplatapus]

Tanks are a 77 gal and 20 gal tied into a common 150 gal sump. Approx 150 lbs of live rock. I've never really had an end population I wanted to reach of either snails or hermits, just wanted a good size clean up crew. But life and work and side projects got me so consumed I started forgetting to just sitting down and watch the tank.

I never noticed until the last few days when I've made a concerted effort to clean up my tank of some algae that's been driving me crazy that there's very little clean up crew left. Trying to figure where they've all gone...