Magnesium deficiency. Could be another micro nute as well, but that golden yellow spotting very much looks like mg def. Epsom salt, say about 1/2 tsp per gallon or water might do the trick, but since you've had this problem for a while, I might go with just a little more salt, say 3/4 to full tsp in gallon of water, water with that only for now, and see what happens, repairs will take place within two days. yellow spotting should disappear, but dead brown leaves will not recover. Feel free to pull the off. a better thing to do is go a hydro shop and get botanicare's calmag and follow the directions on the back for dose rate. Don't give to much or too frequently, as too much won't help, but enough will. I'm wondering if you also have a calcium def there, so calmag should help as it has both. Before you go to the store however, take a look at your fert container ingredients and see if calcium and magnesium are present. If they are, then I'm baffled as to your problem. It could be that you're giving too much of NPK without some micro nutes. I know I seem like a Dynagro salesman in these forums, BUT..... I have to advocate the use of their ferts because you only need one bottle for veg and one for flowering, if you want to buy it. The Dynagro ferts have pretty much all the nutes plants needs, to include things like boron, sulphur, zinc, and yes, calcium and magnesium. Sometimes I think I come across like a jerk but it really does pay to do some homework. For now, try some epsom salt in water and see what happens in a couple of days. You can get it at a pharmacy and it's a cheap fix rather than buying a different fert. Also, in the future please take photos in white light so we can better see color.