help me save my queen!!!!!please!!!!

picture attached, strain is waikiki queen lasts year no problems , then my mother started to get rust spots thenwither and die working from the bottom of the plant and only leaving the tops alive or not.i thought mg defic but i use sweet regularly in my tea. about 20 gallon resivoir little over a quarter cup baseline humic,wormcastings,half rainbowmix half high nitrogen guano,seweedextract, compost, mycoryza , mollasus, and a little sweet, all my other strains are great any help would b gratly appreciated sorry about spelling