Questions - Need some input

In recap; I'm putting together a 120 gallon reef with a sump. I currently have about 80 to 100lbs of Crushed Coral/Argonite from when this tank was a Cichlid/African Lake tank. My LFS owner suggested I go with maybe a 1/2 inch of the Argonite/crushed coral and then add 80 to 120 lbs of Live sand on top of the substrate. Is that necessary? Can the reef survive without Live sand??? whats everyones thoughts??? can I just re-use the CC/Argonite??? I've boiled all the Crushed Coral to clean it. ...

Well, After breaking down my 120 gallon and cleaning it, painting it and other general maintenance. It's back on the stand in the living room, I awoke to find a cat "fish" already in the tank, See photo below . ( so, another wash and wipe...) Yesterday I acquired a 29 gallon long for use as my sump, ( maybe too big, but am running with it...) It was pretty dirty, 3 inches of Wally World Purple Gravel, deap plastic Plants with Blown Insulation into everything. and See before and after ...

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