it's probably too late now but it'd be best to remove as much of the ferts as possible before adding more water so it doesn't take it down into and thru the roots.

also when i 'flush', all it means is for the last month only water is used but not more of it...just no ferts. they only get fertilized twice during each stage anyways...iow, twice during veg and twice during flower. this is for my typical 4-5 month indoor grow. a couple more applications for the outdoor garden...

good luck