Ken

Phosphorous content can vary from about 6% up to about 15% it depends on
the type of solution and how it is controlled. Some general points:

Some solutions are sold as high phosphorous ie < 10% P
The pH of the solution during processing effects the P content - low pH
high P
The hypophosphite content can effect it - high hypo - high P
For ease of solderability low phosphorous content is preferable.

Your processor should know about these effects otherwise how can he
control the solution!!

Regards

Chris Evans
MBD UK