How can you tell how much water to add to incubator?

[pooponshoe]

I have an egg-turner but it blocks my view of the "water troughs" amd I made a mess, poured water out everywhere. How do you best judge this? Do I take out the turner each time? Help!

 

[Cason]

I drew an arrow (with a Sharpie) directly to the beginnings of the troughs <------------------

 

[UrbanMama]

Turkey bastor....perfect amount of water and you can shoot it between the eggs...it works great!