Only using a 750 watt, 220 digital ballast. They're supposed to put out around the same lumens a 1000 watt electronic ballast does. I think it's working a little better than my old 1000 watt was. But I can't say for sure, so many determining factors that I've changed this grow. I got lazy with the log, sorry. I was keeping track of everything in the first 2-3 months, just got lazy....