Thks for ur feedback.
After setting my chiller CA to -1 and temp set to 27 seem like better than before.My chiller cut off for 20min and kick in for 5min when lights on,temp in my sump tank show 27 for the mercury thermometer and 26.1-26.5 for my cheap digital meter.If without lights on it take longer time to kick in but still take only 5min to chill.
Im using weipro4000 rated at 2700l\h from sump to maintank for the chiller,reason using high rated powerhead cos my hose from sump to maintank distance very far around 3-4m.My main tank is 3X2X2 and 2.5X1.5X1.5 for the sump tank,total 3 weipro4000 powerhead in my sump tank,dymax matrix 4X36watt pl lights,dymax OB 2X30watt t5 blue light.