If you ever get a toilet that continues to flush softly, here is a simple solution.
Open the toilet cover. Do not be afraid of the water or if the tank looks dirty. Just scrub it down with cleaners and a good pair of rubber gloves.
Reach in and remove the flapper that covers the drainage from the tank. If you have that soft, black-colored flapper, you are in luck!
Now take you flapper to a nearby sink. Make sure you use a good liquid detergent and a sponge for scrubbing down the slimy, film residue sticking on the it.
After ringing the flapper thoroughly, replace it. Voila!
Now test the toilet by flushing. If it sticks, rejoice! If the flapper doesn’t stick to the drainage after several attempts, buy a new flapper or call a plumber!