How do I Sum value to effect every tick

my event its [every 0.5 seconds set effect parameter index 0 , value +1] and i get syntax error, i tried 1 +1 and i dont get the syntax error but didn't work, i want to add +1 every 0.5 seconds to the value of effect, i tried with a variable ( sprite.valueeffect +1 ) and didn't work, please explain me why?

It might depend on the effect. Which one are you using?

Edit: are you incrementing the value first?

thank you! i solved it using a variable, i just put: every 0.05 seconds -> set effect "pixellated" parameter 0 to sprite.effect , ADD 1 to effect, and now its working!