johnd,
Hi I am trying to convert your "ppm" to conventional concentrations and having trouble. So I will revert to concentration values. In my opion, as my interpretation of fluoride concentrations that have a beneficial effect before/during/after chemo and radiation therapy according to the research I have read is that; 0.05 sodium fluoride for daily use and 0.25 per cent concentration of neutral sodium fluoride for daily use.
As far as the ppm or (parts per million) designation that went the way of the horse drawn carriage in Canada (so I have no clue of what 5000 ppm of fluoride is in todays concentrations)
Cheers,
Mike