So I am trying to find a liquid at room temp., preferably with a low viscosity, non-toxic and non-acidic, that has a specific gravity greater than 1.5 and is fairly cheap. Tall order? I have done a little research and my best bets seem to be Copper Sulfate Pentahydrate, Zinc Chloride, or possibly Sodium Hydroxide(but thats caustic). NaCL solutions seem to max out around 1.2-1.3, and sugar solutions around 1.4 at room temp. I think Copper Sulfate might do the trick, but I cannot figure out what is the highest possible density achievable around room temperature. The specific gravity is 2.284 but it's solubility is pretty low, maybe 300-500g/L? Does anyone know this off-hand or have other chemical suggestions?