we've had our tank setup and running now for about 3 months, and put 3 scarlet crabs, about 20 blue legs, 8 astrea snails, 10 bumble bee snails, and 10 nefarious (or whatever they're called) snails in within about a two month period. we put em in to control the algae and to get little critters to look at instead of just a pile of rock. however, all 3 of th scarlets have died and we are noticing empty crab shells from the blue legs. any idea as of why they may be dieng?