I usually don't use any fertilizer with a ten number for nitrogen. High nitrogen use in tomatoes will produce dark healthy leaves but little fruit. I use a fertilizer specifically blended for tomatoes, it's a 3-3-4. As far as epsom salt is concerned, there is a plethora of info out there with the final result being about half thinks its good, use it, and half thinks its bad, don't use it. You should probably use your own judgement on that.