I got this verbal at 18:23UTC. I contacted TJ before trotting off to the mechanical room. We found that the 'CO2 Y' & 'CO2Y CHILLERS' screens show a discrepancy in flow rates. I went out to the chiller and found that the water level was at 9 (down from 10) so I added 50ml. At 18:55, after I returned to the CR I got another verbal. Trending shows this sudden drop in flowrate (possible leak) or possibly sudden malfunction in flow meter?