I set up my tank n 1971 using dead coral skeletons that I picked up SCUBA diving in Hawaii and the Caribbean. I bleached it in my hotel room and carried it back to my home on my lap on the plane. There was no inspections then and you could bring back a 1955 Oldsmobile with the trunk filled with pregnant Manta Rays if you wanted.
There was no live rock then and only damsels for fish. Oddly enough moorish Idols were an available fish at the very beginning of the hobby and I had one.
That tank is still running and still uses a reverse undergravel filter and although I couldn't get crushed coral then, I have dolomite which may be available in a museum or mausoleum.
Eventually I added "stuff" from the sea and some live rock. Of course bacteria came on live corals and garden soil that I still sometimes add.
To me there is nothing like real live rock right out of the sea and not even cultured, cured or whatever else they do to it.
I realize it is expensive but if you set up a tank correctly, you will never have to spend much money on it.
I am not sure what people are spending money on but I find this hobby comparatively cheap, especially if buying Islands is your other hobby.
I buy a fish for fifty bucks and it lives 15 or 20 years so it costs two bucks a year.
Live rock may cost a few hundred bucks, but if it lasts 50 years, it is cheap.
I am not sure why people keep setting up tanks and have to buy new stuff all the time. A tank should be eternal and once set up, stay up. I really don't get all the problems or extensive costs and I feel I am doing something wrong or not understanding.
I hear all this talk of hitchhikers. Yes there will always be hitchhikers, so what. Those things all live in the sea so consider them free life.
IMO tanks need real life from the sea, no matter what it is. I think bacteria in a bottle is silly as are probiotics. I take probiotics but I also eat natural food to get my "dirt" bacteria which my gut and my fishes gut needs for immunity.
Pro biotics and bacteria in a bottle is only "good" bacteria. Thats great but that stuff will do nothing for immunity or to create biodiversity. Biodiversity is another word for health.
If we remove or never add the correct organisms and micro organisms we will always have problems just is we add medications, especially antibiotics, Red Slime remover or any number of other bottled fish products I feel we screwed up already.
When the hobby started in the US in 1971 we couldn't get medications, so I used people stuff with disastrious results. But I was fairly stupid then. Now I am older, balder and almost, but not quite as stupid.
Now I have no use for medications or anything else.
I also feel if we only use store bought food that is specifically made for aquarium fish we are at a huge loss when it comes to natural gut bacteria and that is the sole reason for disease forums which I feel is a silly forum because fish should never get sick. We make them sick.
Now "I" feel sick so I am going to sit on my boat and ponder the future. Maybe drink a beer while I am at it.