Water changes

Hello, im,looking for opinions. I recently upgraded from a 65 gal to a 125gal . i used about 30 gals of the 65 gal, then about 30 gals of the nutri seawater and filled the rest with reef pro water. 3 weeks in my water levels are still very good. Im used to doing water changed every 2 weeks. Should i just wait a bit for the nitrates to build up a bit more or just change it now. Nitrates are about 5ppm or less. Ph is 8.3 ammonia is at 0. Nitrites at 0. Calcium 420,maganesium 1500 alk 10