Hi there

This is not yours scene,but here is pool scene and rendered with my usual settings:

2 raytrace bounces,pixel samples 6,shading 0.2,displacement 0,Irradiance cache: 0,Sample size:10,Intensity 1.00,Bounces 6,Samples: 1000,Irradiance Cache: 25,Precalculation scale: 1.0,Gamma Correction OFF

 

 

 

Last thing I would try render with Displacement 0 on yours scene,do you really need to have Displacement set at 0.1?

 

Thanks,Jura