Component wall loss due to corrosion is a major safety concern in the petroleum industry. In order to ensure the safe operation of plants, the monitoring of corrosion processes has become a highly soughtafter strategy. Ultrasonic inspection benefits from being a non-invasive approach. However, conventional technologies do not possess the capability for assessing short-term changes. Lately, the use of permanently installed transducers has improved the precision of ultrasonic inspection by several orders of magnitude such that wall losses which take place at 0.1-0.2 mm/year can be detected in the time frame of a few weeks. In this work, the setup for ultrasonic corrosion monitoring undergoes further optimization. In laboratory condition, a nanometer precision can be achieved enabling wall loss rates of 0.1-0.2 mm/year to be resolvable on a daily basis. The current technique provides a highly accurate non-invasive alternative to other established corrosion monitoring methods.