1. Testing  method of iron (ferrous iron) :Take 100ml samples in test sample bottles, add 0.5ml thick hydrochloric acid,  add 2ml Phenanthroline, and 25ml acetic- ammonia solution, test the sample.
2. Testing Method of Iron (ferric iron) :Take 100ml samples in test sample bottles, add 0.5ml thick hydrochloric acid, 2ml  hydroxylamine hydrochloride, shake it well and wait for 5 min, add 2ml phenanthroline, and add 25ml acetic- ammonia solution, test the sample.