first off you have sum problems and steel is not a good grow container...it rusts and i dunno but prolly promote sum type of disease or mold or rot.....looks like you are overfertilizing or underfertilizing and overwatering...do a light flush with 25% peroxide(the kind u use on a cut) and 75% water no ferts and wait like a week b4 you water again u may have sum hope....dont listen to me though im just a noob