Your 75 G
If the tank was mine, I'd remove half the filter material from an establish tank and use it to instantly cycle the new one. The filter media will have the greatest concentration of good bacteria. Just add a few fish, so you don't stress the good bacteria and test the tank water just to keep things safe for the fish. Then slowly add fish and keep testing the water until the tank is stocked. You can replace the media you took from the original tank. Just rinse it well with some of your replacement water and then into the tank. The good bacteria reproduces very quickly and will be up to former levels in a few hours.
Cleaning is really easy. I used a 5 gallon bucket filled with a gallon of warm tap water, a sponge and added a couple of tablespoons of standard aquarium salt to the water. I rinsed it all with more, pure tap water.
"Fear not, my young apprentice. Just change the tank water."