I added 150ml water to the crystal chiller. I also added about 100ml to the diode chiller. 

Note: There was no indication the diode chiller water level was low. The approximately 100ml added to the diode chiller was the remainder in the filler cup from topping off the crystal chiller. Adding the few milliliters of water left in the filler cup after filling the crystal chiller to the diode chiller has been enough to keep the water level above the low limit.