Should I use nutes straight after mixing or not? Canna A + B

I'm curious to know if I should mix the nutrients and then leave them for a while before using/watering.. If so, How long should I leave them before watering?

Many thanks

Also check out my grow in the sig! Thanks guys

Ive never let them stand and they have worked fine, just make sure you put the A in the water first, mix it about then add the B then mix again...

Dont mix a and b and let them stand. You should do what deejay said and put in water seperately. They are in A and B parts because some elements degrade or react if they are mixed for 2 long.