Dont stare directly into either of them or you can cause permanent damage to your eyes.so goy my new hood and 400 wat hps/mh today...very nice but it actually doesnt hurt my eyes like my 12 28watt cfls...should i supplement with cfls...(4 plants) 9 square feet.. i noticed hps are 4100k..im sure ill be fine woth out right...any input appreciated