hermit crabs

[Fishy Poopie]

Hi, I went to the LFS last week to buy 10 small hermit crabs and 1 cleaner shrimp. The worker there said that they will keep my sand clean but in less than 1 week, I have a lot of tiny gray stuff alll over the sand near the rocks. Do hermit crabs poop that much? Seems like my tank got 10 times dirtier in the last 5 days.

 

[Fishy Poopie]

oh forgot to add, i have a 28 gallon nano cube, about 25 lbs of LR, 25lbs of LS. water temp 78-80, ammonia 0, nitriate 0, ph 8.2, nitrate 40. not really sure if those things are poop but hard to believe in 5 days, 10 of them can poop 1000 times. any idea what it can be?