i tried to do some searching but i can't seem to tell if their is magnesium in it.....generally speaking ALL fertilizers have N-P-K (nitrogen - phosphorus - potassium) yours is 7-4-10 which is reasonable for the flowering stage
BUT these other helpers vary GREATLY : Calcium, silicone, sulfur, magnesium
AS WELL as traces of boron, chlorine, manganese, iron, zinc, copper, molybdenum
Try to find out if your fertilizer has magnesium...if not find one that does and go on a cycle or two of nutes that are similar if possible to 7-4-10 (so you don't shock the plant) with magnesium...
this should be done over a period of a couple days, but results should be seen pretty quickly...and like with antibiotics...keep on doing it a couple times after the plant looks healthy gradually going back to your old diet if you wish (again...so you dont shock the plant)
be careful of Epsom salts....agriculture wise salt on of the worst things that can happen to plants...try to get some advice before you proceed...i think it would be hard to measure the strength of the salts especially without a ppm reader
best of luck
HP