no worries mate, how long till harvest, id only start flushing a week before harvest, if you still got a few weeks to go then just mix up a quater strength nute mix and feed with that, just watering will wash out anything the plant needs, so using a quater strength will flush out whats built up but will still put something in for the plant to take in, make sure you have some run off, then you should be ok, then just up the dose again over a couple of feeds, you should be ok till harvest then mate, any problems give me a shout back