[tiki]

Could it need a warmer environment to grow and that's why it doesn't grow in cold water?

[Ditter]

I thought of that after I posted my reply. Maybe it doesn't start growing until it gets into the hot water heater. Last year I got rid of my hot water heater and got one of those new tankless water heaters. It is called 'on demand' because the water is not heated until you turn on the tap. Works great.