You could also try what I did, my waterer is the same as yours. I went to walmart and bought those colored glass rocks (dragon tears) and placed them in the bottom of the tray and I've had good luck so far.
Congrats on everyones babies and soon to be babies!!! We started out last september with 7 and my lab decided she was hungry for chicken and ate 4 of them, so I couldnt resist to order more. I must say that I am officially addicted!!!!
I am so excited!!! I got a call at 6:30 this morning from the post office telling me my new babies were here!! 21 total- 5BR, 4 Ameraucanas, 12 BO. They are so cute and fluffy!