Re. tiling/finishes: look into steel-float concrete. Templates and concepts can be nicked from people/websites talking about concrete countertops. Use fibreglass instead of (or along with) steel: very tough. Can finish with any food/potable-grade sealant as would be used in a rendered water tank. A little white/light grey, grey and ochre all rippled & mottled with an occasional embedded shell behind that Tiger would look... good.
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