I am using .5gph drip to irrigate hops and have run into problems with iron clogging in some of my tube. Have used chlorine followed by n-phuric to lower the ph into the 2.5-4 range to remove remaining iron. Have had some success, but not to the level I need. I have also tried drip-a-tron ( no success) and a product from ch2o(no success). I would like to know if anyone has a product (muriatic,phophoric,hydrogen peroxide) that they have used that worked for them or do I need to lower my ph more? The tube is clean inside until you cut open an emitter and I find a reddish brown deposit under the diaphragm and in the channels. Any information would be appreciated.