First off, to all of you:
Thank you, thank you, thank you.
I really appreciate the advice/ tips/ guidance. I'll be hopping down into my crawl space in the morning to see what's up with everything and to fully decide on what's our next step.
Speaking with my husband (who was the one in the crawl space a few months ago) he thinks that our joists have already been "sistered" or reinforced by the previous owners of our home, so I'm gonna go check that out. If not, it looks like we'll be running by a hardware store or getting a general contractor to help us out if we feel overwhelmed.
Can't wait for this tank though, we're upgrading from a 56... It's going to be a completely new world. Once the tank and stand arrive I'll make sure to start a build thread, too.
Reinforcement updates to come in the morning! Thanks again for all your help.