Acoustic sensors measuring currents in high resolution have been around since the 90s'. Recently researchers have started using them to provide information on suspended sediment load. Acoustical devices tend to be less prone to bio-fouling compared to optical devices and the combination with high frequency velocity measurements allows for a direct estimate of turbulence fluxes of particulate material (e.g. Fugate and Friedrich, 2002). Here we present results of a careful lab evaluation of three such sensors; Two acoustic Doppler Velocimeter providing acoustic backscattering at two different frequencies (16MHz and 6MHz) and a Modular Acoustic Velocity Sensor providing acoustic attenuation at 1.5MHz. We assess the concentration over which we get a linear response and compare measurements of beads of different sizes with the expected theoretical response. Field data is also presented to showcase the performance of this technology in comparison with tried and true optical sensors.