Background insulin

I have had a snack with cp of 6.5. I was wondering whether I need to take my usual 12 background insulin or reduce it.

Your background wont behave like the quick acting will and so no, it will not, or should not, effect your levels after carbs, provided its the correct dose that is....

You should always take your background insulin at the same times every day, as its required to hold you steady, in the absence of carbs/quick acting over the whole 24 hours...