Hi Al,
A strong ammonia smell is undoubtedly caused by indicator dye, as it is the only possible source of ammonia in soda lime. The dye, ethyl violet, is an amine, or an ammonia derivative.
In sodalime dye is their as an indication only. It is not an accurate representation of usage nor is it a permanent colour change. Medical grade soda limes tend to have a higher dye content and therefore increase the potential for the ammonia smell.
You need to ask yourself whether you actually need the indicator dye. Most navies that operate rebreathers now specify non indicating grades especially because of the problems caused by ammonia.
I have an interesting paper, in acrobat format, issued by the Naval Medical Research Institute titled "Chemical Safety of US Naval Fleet Soda Lime", which fully explains the US Navy's experience and their solution. I will happily send to you by e-mail if required.
Best Regards
Ian