A good tank will communicate to his/her healer before they start. Ask your healer a simple question, "big pulls ok with you?". Or something similar.
It warns them what's coming, or communicates to you what pace you should go as well as your healer feels they are about to be taken care of.
Cuz at the end of the day, and this may seem strange in saying but, the tank has to take the responsibility of making things easier for the healer.
You can have a bad healer and still look like a good tank, but it's very difficult to look like a good healer when you have a bad tank.