Thanks for the replies I appreciate it,
So I am using this library because it is an extension of adafruit, It just gives more effects and options for the project that I am working on.
I'm still very new to coding and I did have a look at the fast LED library but a lot of it just went over my head A little bit too complicated for me.
I do think it is a memory issue though I have found that if I run the same code with just one pin output I can run approximately 400 LEDs however if I output to 2 pins I can only run 80led per pin then if I try a 3rd output I can only run 1 led per pin!
I think the library just uses a lot of memory unfortunately I have ordered an esp8266 which has more memory I'm hoping to move the code over to that