Noisy water tank

Hi

I hope someone can help. I have just had a house re plumbed with new bathroom put in. There is a water tank in the attic and every time I flush the toilet, the tank makes loads of noise which goes on for quite a while.

Is there any way this noise can be minimised as it is quite annoying?

Mangos

Certainly comes from the ball valve if the noise is the sound of water.
If that's the case, you could consider replacing it with a silent ball valve from fluidmaster or the likes.