hi

You can quickly figure the size by length x width x depth in iinches then divide by 231 this will give you the gallons

There are dozens of ways to setup a larger tank I kept 8/10 inches of water in the bottom for aquatic plants and fish upper part had driftwood with various types of epiphytes Used the filter system to make a waterfall over part of the back This type is called a paludarium Of course you can use various types of media with streams /pools representing forest or jungle .Almost anything you can imagine can be done . I think the best way is to chose a "theme" and build it to represent a section of a type of habitat .

many other considerations ,such as light , air circulation. temperature.

4/6 foot length tanks give a large choice of equipment to achieve the goals .

Plant selection would be based on how far you want to go particularly with light .there are many orchids and broms not to mention countlesss other types of epis that thrive in the environment The tough part is choosing those that like a warm very humid atmosphere with low lighting. Not the usual types but you can find them. l

I kept most of my plants in small pots to ease maintenance lol You'll be amazed at how fast appropriate choices will grow lol. Or how fast inappropriate choices will decline lol good luck gary