local beach crabs in a reef tank

[reeferious]

75 shorecrabs from outside lower mainland that's what I or my niece brings back from Vancouver island few times a year. in their niche habitat they hide to escape from innumerable predators, harsh environment but i take time to acclimatize them into my reef setups and believe probably doubling their lifespan as I often see quite a few larger ones that come out and gaze around. weight wise would 75 of these little guys equate to one dungenese or rock crab?