I live in a ground-level 2-story condo with three toilets. One on the ground level and two on the upper level. The master bathroom toilet and the downstairs half-bath toilet work great. When you flush the water does all the right things. The guest bedroom toilet however does not flush properly and my husband and I are at a total loss of what could possibly be the matter.

When you flush this toilet the bowl does not drain completely. Holding down the handle causes it to drain better, but still not the full bowl-emptying and refilling that should be happening. We pulled the toilet off and snaked the drain (25 foot snake)- nothing. We replaced the innards of the tank- nothing. We don't know how one toilet could function so poorly when the others work great.

Any ideas? Suggestions on how to investigate this problem further? My husband thinks possibly replacing the whole toilet altogether might fix it, but I'm skeptical. If there's no clog in the physical toilet, replacing it won't make it flush better, right?