new 90 builds lights

[Sydoriakp]

am buying a new hosue and am building a new 90 gallon setup I have two 250 watt mhs 20k radium fired by a dual galaxy electronic ballast. what is a nice way to supplement these? .... a cheap way ...electric bill... wise ...and equiptment cost... I was thinking of one reer brite led strip in front but will I need to do one in the back too? I don't have a huge bugget and if its just supplement does it really matter as a will angle the one in front towards middle of tank..... any comments are appreciated ty so much