Proper height and slope for reverse negative edge spa

[spool]

Finalizing design with PB for our spring time build. We're considering changing the spa spill over feature to a reverse negative edge similar to the image below. Our spa height is 18" higher than the pool. What is the an appropriate spa height and slope angle to maintain a nice even sheet of water flowing over the edge?

 

[Patrick_B]

Sorry, that's a question for your designer that most of us will have a hard time answering correctly.

 

[JasonLion]

It is more about construction precision than it is about height and slope. Mostly it needs to be installed exceedingly level and uniform to get that uniform sheet of water effect.

 

[spool]

Thanks guys, I figured as much. When the snow melts the PB will be taking us to a few nearby pools with the same design.