In this work, various in-situ detection schemes are explored to observe the hyperpolarized acetonitrile solvent (with naturally abundant N spins) at both zero field (ZF), in our experiments <100 pT, and ultra-low field (ULF), in our experiments 2 µT. The observed hyperpolarization was employed for DC-pulse calibration, SABRE-SHEATH field profile investigation. Finally, it's applied to study the relaxation properties of the sample at different fields.