I would take a sample of your water to the lfs ( if local ) just to confirm your test results,
I think your being mislead with ammonia results, and stop testing for it, concentrate on salinity, nitrate, phosphate, Alkalinity, PH , calcium, magnesium.
Are you carbon dosing? To me looks like a bacterial bloom, if so oxygen could be a problem, point wavemaker to surface.
Hanna checkers worth having, phosphate low range, Alkalinity DKH reading, Nitrate high range.
Most important, take sample to lfs, don,t let things get out of control buy adding chemicals for quick fix, your tank is young and will go through many changes