Ongoing pH issues

Water, water, feed, water, water, feed is the most useful schedule, that way the plant uses everything you added before you add any more nutrients. Yes, feeding each and every irrigation can lead to nutrient salts building up to toxic levels, no need to flush, just start with the water, water, feed routine. I would suggest going to 18/6, 4 hours of "sleep" may not be quite enough for a healthy metabolism. You won't be missing out on anything by going to 18/6, in fact, results may even be better from a plant that is getting sufficient "sleep". I would also be adding a cal/mag supplement and a soluble blend of trace elements (available at nearly every garden centre) to boost her health. Hope this helps, Organoman.