flushing agents are useless things. if you need such a thing or to constantly flush, a formula change is a better route to go... so you don't have to do such things in future.
flushing is over-prescribed like ADD is over-diagnsoed, lol. it's something people do to feel like they are doing something but it's more of a net-negative than a positive.
flushing is for catastrophic failure in your root zone. if instructions lead to it being required, they are simply instructing you to feed WAY too much.