need help

[possitive k]

i have a 90gal setup been running for over a year now with no major problems.i just recently got a bunch of live rock from a friend(about 100lbs) and added it to my tank, i allready had about 100 lbs in there. now my nitrate whent through the roof and the ammoina whent up too, not as much though. i did a water change of about 30% the other day and checked paramiters agian today with no change. what should i do, just keep doin water changes an hope for the best.

ammonia-0.25ppm
nitrate-80ppm
nitrite-0ppm
temp-81
salinity-.026

Thanks Kristian.