Thanks for the information.
Just to close this topic out for future reference, I did get the ingredient information from Lonza (Parent company for both the Brilliance and Leisure Time brands) on the following products:
Leisure Time Defender:GLYCINE, N- (2-BIS(CARBOXMETHYL)AMINO)ETHYL)-N-2-HYDROXYETHYL)-, Trisodium Salt 139-89-9
Citric Acid 77-92-9
Trisodium nitrilotriacetate 5064-31-3Leisure Time Metal Gon:1-Hydroxyethane 1,1diphosphonic Acid 2809-21-4Brilliance Metal and Stain Control:1-Hydroxyethane 1,1diphosphonic Acid 2809-21-4Thus as of August 2014 Brilliance Metal and Stain Control appears to contain the same ingredient as Leisure Time Metal Gon. Same parent company, same ingredients but two completely different recommended dosages
With Metal Gon your suppose to pour 16 oz into the spa at fill and follow it up with weekly doses of Defender. With Brilliance they recommend 1.5 oz for every 150gal of water at fill and a weekly follow up of the same Brilliance product at the same dose rate as the initial fill.
On the other hand Leisure Time Defender is a concoction of stuff. I understand citric acids role but do not understand the benefits of the other two ingredients in the Defender product.