Turn on LEDS one after another
Okay so i figured it out. The problem is that the for loop is starting at 0 and counting all the way up to the midpoint. What I wanted is for it to light all the LEDs that are at j and below. So I changed it to iterate down instead of up. Here's the new loop:

for(int l = j; l &lt; midpoint &amp; l &gt; -1; l--){
   leds[l] = CRGB (R, G, B);
}


The extra qualifier l &gt; -1 is to make sure that it doesn't try to go below leds[0]