Kilner jar beach theme table centrepieces

I wonder if anyone could help me. I’ve been asked to create 6 sea/sand type centrepieces for an upcoming party. The tables I need them for are huge, 10-12 seaters so need something substantial. Killers are quite expensive and maybe not big enough so looking at some big glass jars from Ikea. I’m thinking to add sand, maybe natural/blue or similar, in layers topped with pebbles, shells etc. I’d then put in some led string lights (not allowed candles), attach aband off hessian or wind round some string and add maybe a dangling starfish or something.

My questions are, do you think they would be effective? What kind of sand and where to buy? Colours sand? Do I need special sand? Any ideas on buying big jars - I won’t need lids. I’ll get some driftwood to put on the table too. Any ideas would help, thanks.