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I startes with totally sterile rock, sand, and water i dosed with an on the shelf nitrifying bacteria from my lfs. I also got a handful of rubble from a display tank of a good friend of mine who has some amazing tanks and corals. Then i threw in a frozen cube of misiss shrimp. (Secert family recipe dont tell anyone)
OP, I have been dealing with the same situation of seeding a new tank with seed/live rock from old tank... how did you go about the cycle? Used a table shrimp after seeding it or pure ammonia? I'm debating if I should add a fish after I added my live rock from the old tank to get a "mini" cycle going and then transfer the rest...
Also, amazing work with the cabinet! I never had the guts to build one myself, but seeing yours gave me a little more confidence!