Sick tank. What to get? What to do?

#1
First of all, I would like to say thank you to all who have helped me with my first community fish tank. Everyones help and understanding of my frustration has been well appreciated.

Now as it stands, I am going to treat my entire 50 gallon tank. Just for precaution tank.

However, I want to build up a 10 gallon hospital tank. My question is, what do i need?

Do I need gravel? What kind of filters? Is this something that I can keep disassembled and then bring it up on a whim, when I see my fish are diseased or injured?

Any assistance is greatly appreciated. Thanks!

-Philippe