When I set up my last tank (75g)
I added some gravel taken from a very established aquarium and added it to the filter. I also added a LOT of starter microbes, then I put in a little fish food every day. I had everything running including wave makers and light on 24/7. I did put in nerite snails and glass shrimp as a clean up crew. The snails are still there (and they are huge now) but the shrimp got eaten....
Now keep in mind, my tank is only 10% of what you have (75g)
You have an awesome tank. One day maybe. You haves a dream tank!