If you have too much fertilizer its not going to make any difference how much you raise the PH, the fert is still there and it will burn your plants. To flush out the fertilizer pour 3 times the volume of the pot of clean fresh water through. So if its a 5 gallon pot, you need to pour 15 gallons of water in the pot and let it all drain out. Then hope and pray and leave the plant alone for a few days.