On Tue, 30 Jul 2013 19:52:37 +0000, Danny D. wrote:

I'm not sure which of the two floor drains in the spa is the main as
they both suck water when the main filter pump is running. I assume
they're 50:50 as there isn't any way to tell the difference other than
they look slightly different.

I couldn't tell which of the two spa floor drains was the main and which
was the safety though, as they both seemed to suck up dye equally:

http://farm4.staticflickr.com/3781/9...0dca9e19_o.jpg