The temperatures here in Northeast, Indiana are supposed to drop into the very low 30s on Tuesday of this week, and it looks like the low temperatures are going to be in the low-to-mid 30s all the way through Saturday. The highs will be right around 50 degrees. I have already started feeding the Koi since the water temp is around 60 degrees. My question is: Should I turn off the pumps? I'm worried that the 4000 GPH flowing down the waterfall will cause a drastic water temp. drop. What do you guys normally do? This is my first spring with having my koi pond, so I would appreciate input. Thanks,