Problem with phosphates. New pool

Hello I'm having an issue with my phosphate level in my pool. The pool was recently replastered within 2 and a half months. My pool service informed me that my faucet level is very high. Around 1000 ppm. Otherwise my pool is well balanced. The only issue I have is high calcium levels due to the city water.


We added phosphate free and let the pool filter run overnight. The next morning the phosphates had dropped to 300 ppm. However, by the afternoon they were back up to over 1000. So we added another round of phosphate free and now we are waiting a solid 2 days to let it run its course.

My question is 1 what could be causing the phosphates to jump up so high in such a short time our tap water has very little phosphates in it. Has anyone ever heard of new plaster having this issue?