Different crab in my order?

[Grant maj]

Originally Posted by Myka

Like I said, Scarlet Hermits are the lesser of the evils. I have 15 of them in my 50-gallon tank along with a few Astraea, Mexican Turbos, Ring Cowrie, and even a few Cerith. The Scarlets don't touch them. There was one Blue Leg Hermit in there and he killed off most of the Cerith before he got banished. Generally, the bigger snails are resistant to hermit predation.

How many are required? I have a 90gallon. And I was reading on jlaquatics site and they recommend 70 crabs and 60 snails? Is this correct?