So i have read up on pull up/down resistors. And never new of this floating state phenomenon 
If the relay when not activated is CLOSED, and i am sending a digital high signal from one pin through the relay and listening on another pin i think i will use a 10K pull up resistor on the input (listening pin) from the arduinos vcc?
Also i read that i might need two resistors one from vcc to the input pin and one from the pin to ground (or is this second resistor not needed because it is already inbuilt into the arduino? But then i read that arduinos have an internal pull up pin and that can be enabled by code - do i need to use this?
Thanks