i believe sicce extrema seem to have a high head loss according to the chart provided by them. i am unsure of the sicce multi ...
the recommended minimum flow rate is 900l/hr f i still remember correctly but they did not provide the upper limit like arctica... i guess a rate of 1500l/h through the chiller is still okie. considering the head loss and pipe friction, my flow through the chiller might be just 1500l/hr.
anyway if u find ur 'kick in time' unusually short , the flow might be too slow , usually long, the flow is too fast . sit in front of ur tank and start using ur stop watch =)