Too many complications to explain. (1) Surprised that phonons can travel fast enough round the dark matter in the galaxy to produce the required isotropic effect on gravity. (2) Temperature of the universe appears to be too high 2.7 K to allow equilibrium temperature of 0.1mK (3) Black holes nuclear reactions in stars are massive sources of heat and turbulence in the superfluid which could cause the loss of its superfluid characteristics (4) Still need to explain where these minute particles come from in the first place (5) Seems to add a level of complexity “Occam’s Razor” which I am intuitively uncomfortable about!