While doing my usual Monday morning PSL checks I noticed the chiller was throwing an alarm.  Upon investigating I found it throwing a Low Level alarm, so I added 150mL of water to top it off.  This stopped the alarm.  According to the fill log and a quick alog search we have been adding ~150mL every 6 weeks or so; this is in contrast to the old PSL chiller (O1 through O3), where we were adding ~150mL on a weekly basis.  Everything with the chiller looked OK.