Close about 4 to 5 inches and you can almost let the plant the light LOLOL without any burns, had to take a company trip and that how I found out! LOLOL
YeAH they may look stretched out in the pics cus i took clones a week ago so they don't look bushy, THERE NICE AND SHORT FOOT AND HALF pics do no justice !
Sorry if you were talking about plasma, They can get pricYYY try the bargin big i think EDS something like that there about $500 and some change!
Good luck post pics if yah get one and your progress