No issue with changing brands mid flower.You can't beat Advanced Nutrients.Almost all nutrients brands are built on the horticulture industry like tomatos and peppers.Advanced nutrients have had a number of in house scientists developing their line over many years.The majority of the big growers in the US use them.You only have to check their site to see how "advanced" they are.They do it all,organic,mineral and coco and its ph perfect so no messing around with ph.Iv been gowing hydriponically for over 30yrs and have used adavanced for over 10 so know what I'm talking about.They arent cheap but you get what you pay for for the most part.