Nanofluids are constituted of typical heat transfer fluids (water, ethylene glycol) into which nano-sized particles are dispersed to enhance their heat transfer.¹  Nanoparticles are resistant to gravitational sedimentation due to their enhanced Brownian motion compared to micron-sized particles. However, nanoparticles in suspension are still subject to aggregation over time due to interparticle collisions, which degrade the stability of nanofluids.²  In order to use nanofluids in industrial processes, long-term stability is required. In previous research, sedimentation and agglomeration have been observed during investigation of a dilute alumina–water nanofluid in a natural convection cell.³  These issues were resolved through the manipulation of the nanofluid pH, decreasing it to a value far from the isoelectric point (IEP) of the nanopowder. This resulted in a net surface charge on the dispersed phase, enhancing the stability of the nanofluid through inter-particle repulsion due to electrostatic forces. For one type of alumina nanoparticles, this was achieved through the addition of acetic acid. For another type of alumina nanoparticles, this reduction in pH was achieved through extensive sonication in an ultrasonic bath alone.⁴