Spoke tension, rather than spoke quality, is to blame. If you replace them one at a time, and correct the spoke tension now, they may stop popping; or maybe not. The old ones, and maybe (some of) the new ones are already fatigued to near the breaking point. I'm afraid you have to replace them all, and get the tension right this time.

I know I'm in the minority here, but I don't believe you get a better wheel by paying extra for a more expensive brand of spokes.