LOL Yea, well maybe a ROOM can't be over-lit, but a 4' crawl space with a 1000w is going to cause a lot of problems. You would almost have to SOG small plants to keep enough distance from them to keep from frying them!

You may find a splitter that would do that, and it would work, but why doesn't he just go get two 400's and sell the 1000? He's gonna have enough challenges growing in a crawl space as it is. I would recommend dropping back and punting and go get the lights that make sense for a crawl space. Maybe one of the new Induction lights? He he Mixing and matching ballasts and lights can be very dangerous. Stay within design parameters of electrical devices and avoid burning down houses.