Good morning! When we started we got a 75 gal 4’ and I said, “wow that’s a really big tank”! But when we went to Chicago to the aquarium and I saw how big my little fish were going to get I said, “ we’re gonna need a bigger tank!” So we found the 300gal by accident on sale brand new and bought it but it took a year to get everything together we needed. Thank goodness we have a family room that is an addition to our house and is build on a crawl space instead of basement, we had to put 4 jacks up under the joices to support the weight. Just Incase! We drilled a whole in floor and plumbed down through the crawl space 20ft to regular basement and my husband built his own sump out of a 120gal fresh water tank we got in line for 100$. Works well and is super convenient for water changes and maintenance. We also have a 180gal fish only in the living room, wanted bigger but wasn’t sure about the weight. We also drilled the plumbing through the floor to basement. So we have two sumps in the basement, RODI water station and had a plumber install a large double utility sink! Have to give up Harley’s to pay for fish! Now I wish we had done a 500gal. Next house will for sure build in a 500gal tank. Maybe 5-7yrs! What state are you in? We are in Wisconsin and have a great LFS about 45 min from us. Owner has been to our house and helped with the sump and design. Good luck and have fun. Glad you are doing it together makes it so much better. The planning was fun for us. I am on call today and just watching my fish!