Replacements, how often?

[thecichlidpleco]

How often should I add more clean up crew members to my tank. I just had two hermits die on me, either fighting each other or killed by six-line. Anyone know a lifespan of hermits. Also, my specific gravity was up to 1.030, but nothing else died, including my peppermints, so I dont think that was the problem. LEt me know what you guys think.

 

[graveyardworm]

Hermits can live a long time. I add more as populations decline which actually hasnt been in quite awhile now. BTW I dont keep hermits they are too destructive IMO. The only ones I have are ones which were bought several years ago, and havent perished yet.