I am so sorry to hear this, this is so sad. I don't know about the water, but your message just tore my heart up. I have two male Finches, One I've had for 10 yrs and the other is 3, he replaced a 6 yr old who died from a fall. It was devastating to lose him, I can't imagine how you feel losing six. So sorry. :/ I hope you discover the problem.