Microcracks On American Standard Champion 4 Tank

[vbg]

I purchased this toilet Model 2793.128NTS.020 in July of 2018. It has been ghost flushing for quite a while.
I have replaced the rubber flush valve seal numerous times. After contacting American Standard about the issue they sent a replacement flush valve. After the install there was no change to the problem. I even replaced the flush valve seal on the new flush valve. I put food coloring in the take and within an hour is showed up in the bowl. I reached out to the company once more and they told me there were probably microcracks in the procelain on the bottom of the tank at the flush valve seating area. Water never appeared on the floor, bottom of the tank, tank bolts or around the area where the tank sits on the bowl. They are sending a replacement tank.

 

[Reach4]

If you turn off the supply water, and see how far the water will fall, you can distinguish a leak at the flush valve seat vs the tank-to-valve connection.

Also, if the water is just above where the leak is, you can drop some food coloring drops, and watch the flow.