New marine starter tank

Hi I have taken the step off moving to marine from African cichlids, I have purchased a fluval m90 (135l) tank from the LFS with heater, return pump, skimmer & power head, and I am curious to what else I would need to establish the tank. I understand live rock & ro water but is there a need for "live sand" ? Or are other options available ? The tank itself was an ex display tank until this last week. Stocking wise I was thinking a couple of clownfish, a regal tang and a couple of banggai cardinal fish, and the clean up crew of hermit crab, shrimp etc... All and any help appreciated
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