I rent a house... the toilet is old over 20 yrs is say. It flushes in a swirling motion, and is very sluggish. Liquids flush fine, but paper, tampons and sometimes poop residue comes back and it will look as if the toilet is going to back up before it flushes. Liquids only don't do it. Will a new toilet/tank fix this or is it something else,possibly?