Slow ghost flushing?

I just replaced all the internal parts for my American Standard Champion 4 including the bolts from the tank to the bowl and the gasket between the tank and bowl. The only thing not brand new is the water supply line and the actual tank and bowl.

I believe I’m having very slow ghost flushing where I’m losing water in my tank and I think the bowl too.

How do I keep from my water levels in the tank and bowl from going down?