GloTell™ is a dark red liquid, density 1.15 at 20° C, fully soluble in anhydrous ammonia. It is detectable by fluorescence at 0.1 ppb. Non-carcinogenic and non-mutagenic, it has been used in various environmental applications since the early 1960s. It photo-degrades within a few days of soil application, and will not bioaccumulate. It is a long-chain complex carbon molecule; it is stable at room temperature and water-soluble.

When GloTell™ is placed in anhydrous ammonia, it tints the ammonia a light yellow color. GloTell™ is not carried in the vapor phase of ammonia, and will remain where liquid anhydrous ammonia touches. Traces of GloTell™ are visibly pink to a concentration of approximately 10 ppm, and are detectable by fluorescence at a much lower level.

Methamphetamine produced with GloTell-containing anhydrous ammonia is discolored, sticky, and hygroscopic. It is difficult to smoke. Handling GloTell-stained methamphetamine will result in staining of hands and utensils. Glassware and other containers used for the manufacture of methamphetamine will also be stained by the presence of GloTell™.
Has anyone here used Glotell in their NH3 refrigeration system? It appears they have tested it under ASHRAE 97 but I would sure love to know it worked in real life before I have to replace a couple tons of ammonia.

http://www.glotell.com/index2.htm

It's a damned shame that it doesn't dissolve in the vapor phase because it would make a wonderful leak detector if it did.