A densitometer in the present disclosure comprises tension measuring devices that send tension measurements to a measurement module enabling the measurement module to estimate fluid density with increased accuracy. The densitometer measures sample fluid density by vibrating the sample fluid and measuring the resonant frequency of the sample fluid, then estimating the sample fluid density based on this resonant frequency. A set of tension measuring devices affixed to a tube of the densitometer measure external forces on the tube due to O-ring seals and other operational conditions. The sample fluid density estimate uses these tension measurements to take into account O-ring friction and other external forces applied to the densitometer to improve the accuracy of the calculated density.