Here are my findings:
1) User box instead of plane for the pool water. It *should not* cause any issues, but better safe than sorry.
2) Unplug the RaySwitch map from the pool water reflection/refraction color. For some reason it seems that just plugging it cuts rays/s by half. So just use pure white or some specific color, if possible. It will be best not to use it at all.
3) Bump map on the water surface seems to be too strong, so it scatters caustics in all directions. Lowering the bump intensity to something like 0,1 helps greatly. You can also try using displacement instead of bump (autobump will take care of the rest and it is enabled by default).
4) Optionally: use 3ds Max native noise maps instead of Siger Noise. There is nothing wrong with using them, but they are definitely more detailed and more resource-heavy than standard maps.
Another thing is that the scene is quite large compared to the area which is visible and which should show caustics. It's a known issue that caustics will render slower/look worse in large scenes, and we already have a feature request logged for rendering caustics only in specified area (e.g. on specific materials only, or within some specific radius).
Let me know if those hints help or not.
