Ph v ta

[waterbear]

I don't think I can take credit for that explanation since I believe waterbear (Evan) was the first to explain it that way though it's been so long that I don't remember exactly who said what first -- not that it matters.

http://www.poolforum.com/pf2/showthr...9434#post49434
My first post in the thread about halfway down in bold.