It is very common to get some sulfur odors when doing apples, however, usually it is transient, and not that strong. Having really strong odors that don't clear is a sign of undernourished yeast - and even if you gave enough nitrogen, the product you are using doesn't provide the key vitamins (like pantothenate and pyridoxine) that are needed to keep sulfur odors from being produced. For future batches, you'll want to get some yeast energizer (tannish powder) such as Fermaid K that provides these essential nutrients in addition to the nitrogen from the DAP and urea.
During a routine, well nourished apple fermentation, by the time it is done, the sulfur has usually dissipated. If your batch is really stinky now and has completed fermentation (gravity no longer dropping), it needs to be treated or you may wind up with more-complex sulfur compounds that won't go away. A splash racking is helpful, and then treating with yeast hulls sometimes helps, but more often than not, you will need to treat this with copper - racking through some copper pipe, or with a copper scrub pad, or stirring with some copper.
This should quickly eliminated the H2S and mercaptans that are causing the stink, and with age, the apple will come back.
Endeavor to persevere!
Medsen
During a routine, well nourished apple fermentation, by the time it is done, the sulfur has usually dissipated. If your batch is really stinky now and has completed fermentation (gravity no longer dropping), it needs to be treated or you may wind up with more-complex sulfur compounds that won't go away. A splash racking is helpful, and then treating with yeast hulls sometimes helps, but more often than not, you will need to treat this with copper - racking through some copper pipe, or with a copper scrub pad, or stirring with some copper.
This should quickly eliminated the H2S and mercaptans that are causing the stink, and with age, the apple will come back.
Endeavor to persevere!
Medsen