That is a good question. Those packages, IMO
, are more for an established tank, with plenty of food for those numbers of clean up critters. In your situation, I would start with 20 or so of different snails, like nassis, cerith, turbos, nerite. I generally order mine online, at what ever the cut off is for the cheaper price. Personally, I only have 3 hermits in my 55G, I am not really a big fan, but others love them. Make sure you provide them with spare, larger shells for them to move into, otherwise they like to take shells from whomever they please. Crabs can be tricky, they tend to get agressive as they get bigger and may eat smaller fish or inverts, that they can catch. I don't have one, but I like the decorator crabs. I took in some algae to my LFS
, she put it in the tank with one and he chopped it up and carries it around, they aren't a good idea if corals are present in the tank, as they can grab them and attach it to themselves, the same probably goes with a pincushion urchin.