And the thing about a product like clearex is that it's a salt based solution with 3% sugars added. The reason the sugars are there is to give the plant energy at a time when you're looking to clear the nutes out of your medium. In all reality, you don't even need to use the flushing products as watering with a light nute solution with essentially flush just as effectively.
I'm not trying to argue for or against a particular method, but at $30 per gallon for a proper salt-based leaching solution, that's pretty cheap.