The beauty of a good flushing is that you are not adding anything new to the problem that could significantly increase the speed of the death of your plant. In my opinion the weak link of water soluble nutes is the possibility for salt build up. Most plants would benifit from a good rinse now and then so I feel it's always a good place to start.
If in fact it is nute burn related and you do flush it, you should see positive response within 12 hrs. or so. Dead leaves do not come back to life, there is only so much you can expect along those lines but if this is the solution you should see almost imediate response and you haven't spent a dime nor have you had to make another tripto the hydro store. You are also not adding a more confusing layer of shit onto an already confusing problem. I believe that almost all problems we as growers face regarding our plants are caused by us. Operator error!! Get back to square one with a flush of phed water and proceed with deliberate purpose on a basic schedule of maintanance.
If that doesn't work start with all the other courses you feel will help but start with start and go from there
btw, it ain't heat or lights
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