after ick loss of fish

about a month ago i battled ick. did the ick away thing. did the raise temp and salt thing for about 3 weeks. ick is gone. cleaned tank, checked parameters and all were the same as always. amonia 1.0,nitrite 0, nitrate 5,ph is 8.4, but it hasalways been that high. i understand fish will adapt to that after a while. water is very soft with high alkalinity, off the chart. now i am loosing a fish every few days. first they get a milky sheen on their skin than start to shimmy and then swim with their nose to the ground. all the other fish attack it at this point. than they die. help.

i'm using the liquid test drops. also the test strips. they both show the same. i did a 25% water change today and the amonia dropped to 0. ph is still off the charts along with the alkalinity.