Flushing Problem / Question?

Withing a single ebb flow system there are two distinct strains, a quick flowering G13 and Skunk No. 1. The G13 is just about finished up while the skunk has about 2-3 more weeks to go. I don't want to deprive the skunk of necessary nutrients, but I don't want chemical tasting G13. Thoughts, Suggestions? Thanks.

the plant doesnt use nutrients after 5-6 weeks, so any nutes after that is a waste, and will be stored in bud during curing. Its already too late to completely flush, but flush now until harvest.
Pour 3 times the amount of water for pot size, to flush any existing nutes in soil.