Wow, 141 gallons of additional aquarium tank space! And you already had that 125 and I believe at least two 20-gallon predecessor aquariums. Just by weight, setting up those involves well over a ton and a half perhaps more than 3,400 pounds/ 1542 kilograms. And that is without stands and may under estimate the weight of the aquariums themselves

I have more than double that in weight in set-ups, stands and water storage. They are spread across one room and bits of two others. I am grateful for a slab foundation. When we lived in a three floor townhouse, much of that, of necessity, was in the basement.

I hope you have safe places to store those tanks until you can use them. Garages or basements are where things like that often gravitate. I'm sure you will make a point of not storing them near paint strippers, pesticides, gasoline or chemicals which might be taken up by an aquarium.

I never could store anything of that sort in my Dad's garage for just those reasons. That is mentioned not for your sake so much as for that of  someone reading along.

Your parents sound pretty supportive. As you know,  you will also have to work out what available space an aquarium could take. How well the floor can support the tank, the temperature and lack of drafts in a location, access to safe electricity, how close the tank is to a source of water and a place to dump water, location out of direct sunshine (which can devastate the tank with algae) and how an aquarium will blend in with a room's decor will all be among the factors you will consider.