Im currently running 3-250w mh on mh 325g tank, i want to add another light but dont have ballast. The 3 i currently have are all ice cap ballasts. Yes i know there old but they do still work. So my question is what should i buy for the 4th ballast? And if i get a different brand ballast will i get different light from it and have to buy 4 new ballasts?

