I would stop worrying about the nitrates. If you kill the algae in the pool, then the nitrates don't matter. If you want to drain/refill part of the water, then I would drain/refill before killing the algae so that you're not wasting all the chlorine to kill the algae, then draining that nice, clean water out of the pool. However, I still think you could just stop using stabilized chlorine and run a higher Cl pool,, especially if you want to get swimming during this season. Folks with sensitive skin shouldn't have any problem with this type of water--a pool with a CYA of 160 and Cl of 10 is no more irritating to the skin than a CYa of 30 and Cl of 5. The chloramines are normally what will irritate the skin, but if you keep your chlorine at the appropriate level, you shouldn't have those anyway.

It's your pool and you are the one to ultimately make the decision. However, I want to caution you that completely draining the pool, if you have a high water table, can cause the pool to literally float out of the ground. If you decide to go that route, I'd make sure you have some professionals to help do the job.