I don't know if it has any bearing on what you are looking for; however, what you have given, "Normal seawater at 17% salinity, the density is 1025..." sounds quite strange. Where is this "normal", and by any chance to you mean instead a SPECIFIC GRAVITY of 1.025 (that would in my opinion be more "normal", at least for a seawater of say 3.5% or so salinity)?