I understand. I just looked up the halacha as brought down in the Kitzur.
. It is sixty neshimos (which he says is approximately half an hr)
I wasnt paying attention to what I was reading because I was looking up the number of neshimos, but I think I saw him say that if you do wash negel vaaser in the middle of the night and then go back to sleep and wake up after daybreak you should wash again, without a bracha. Need to double check.