Multiple addressable LED strands

HI i am trying to run 8 x 50 addressable led strands (neopixels). i have the code that i want to use but i am unable to run more than 2 strands at a time i understand the signal for the addressable part of the strands is voltage sensitive ? so is there a amplifier available to bost the signal for the other 6 strands (or all 8) or can the code be modified to have 8 out puts from the board ?.if so how i have limited coding experience.
The code i am using is a example code (color pallet) i have also tried to incoperate the code into the mirroring code but with no success from the arduino library
any advice help very appreciated