The dial on my water meter that detects water flow (I think this is how one detects a leak) normally moves in a counter clockwise direction when water is flowing from a sink etc. When water was not flowing, the dial would stop then creep slowly still in a counter clockwise direction. I suspected a leak and then went through the house turning off the water to the toilets one by one. Found one of them that stopped the dial from moving and left it off overnight. By morning the tank was empty which to me indicated a leaky toilet. I replaced the flapper and all seemed OK once the toilet was turned back on. No dial movement. About a day later I noticed the dial moving again slowly - this time in a clockwise direction. I turn off the same toilet and it stops.

I am totally confused. Can anyone offer some advice?
Much thanks in advance.

[gonna tell a story]
About 20 years ago I was working with an electrician that had a similar problem. He changed the flapper, it did not work. He changed the flush valve, it didn't work. He changed the tank to bowl bolts and gasket, it didn't work. He even changed the fill valve, it didn't work either. He asked me if I could fix his toilet. I said, 'yes, in about 2 minutes'. He was befuddled. He had even epoxyed the tank to the bowl. I made arrangement to go over and look, and it was just as I expected. The fill tube was pushed way down into the overflow tube and it was syphoning the water out of the tank into the overflow tube. I simply pulled the fill tube out, clipped it, and reinstalled it above the water level in the tank.
He was astonished, but it worked.
Check other things too, but don't forget the tube.