The VL53L1X and the VL53L1CB are nearly the same hardware, but the software is different. The range is done entirely on chip when using the L1X, but the L1CB works differently.
The L1CB uploads the raw data (histograms) to your host and it's your MCU that gets the range.
The advantage is you get a better, longer range. The disadvantage is software complexity (although we provide the code) and you can no longer get interrupts.
Surface water is interesting in that the photons that hit perpendicularly return the right answer. All the other photons only confuse the issue. So, using a narrow Region of Interest is beneficial.
Unless you are going for a particularly deep pool of water, I see no advantage to the VL53L1CB.
You might also consider the VL53L4CD. It's limited to 1.3M, but it has a narrower Field of View and it's quite a bit less expensive. Same footprint though.
- john