In article , ~Vicki ~ wrote:

currently looking at homes. This will help me decide on either a slab
built home or one with a crawl space.

You can support a 400 gal tank on the first floor of a house with a
basement and standard floor joists. You will need to support that tank
from the basement. But that is hardly difficult.

In most houses you can place a 50gal tank anywhere you want. Larger
then that and you need to start thinking about how the tank is placed
in relation to the structure of the house: perpendicular to the floor
joists, against an outside or supported wall. Additional support from
below may be required. This is all very general. Some houses cannot
support a 50gal properly. IE Netmax's 50 gal and floor bounce.

Again it all depends on the age of your house, construction method,
size of the tank, and desired placement of the tank. The proper
question to ask is: I want this size tank where can I put it?