Help Please Some One...flourecent Lights

i need help can't find it any where else...i called and electrician but he wants to come out..i understand..

here goes i have 3(three) Flourecent lights in series...i ran a new wire from a 20 amp breaker...to the first light..it is a double tube 4 foot light......at the end of the 4 foot flourecent tube i ran 2 seperate wires to the 2(two)4 FOOT single tube flourecent lights out each side in the end...okay here's the puzzzler...i turned the breaker on....and puzzzzled the 2(two) single tube flourecent lights burn but the double tube looks like it's on low voltage....and then some times dont even burn...okay there all 120 volt ballast lights...can you help please..thank you..Badd