Buffering coir in nutrient solution?

[Magnetonastick]

So I'm going to be starting my first grow in coco coir using Canna Coco A + B.

I'm using a cheap coco coir brand and I have read the need to wash and buffer prior to use. I understand most people use a solution of Calmag.

I don't have any Calmag at my disposal, so I was wondering if soaking my coir in A + B would also do the trick? Or is Calmag my only option?

Thanks