It seems that 4 months is an awful long time for clones. They will get too big. I vegged my clones under 4- 40w flouros for about 30 days and they were about 1 1/2 feet tall. I also run the lights 24/7 which alot of people disagree with but it works for me. After putting them under the 1000w hps they stretched quite a bit to where I have to LST to keep from burning from the light. When I first bought the 1000 hps I thought it was way overkill, but as the plants got bigger I was very happy I went with the "big gun"