a comparison test from USA , hortilux got the best PAR 1960μmol/s, but this result was test under reflector, Philips 2100μmol/s test in integrating sphere , no reflector. So without reflector the PAR of hortilux will decrease. And the PAR of other brands are too low, it is not good as they said, are they real HPS grow light? For 400v 1000w at least should be higher than 1850μmol/s as Philips master greenpower TD EL standard .