Seachem flourish iron is a highly concentrated 10 000 mgl ferrous iron fe2 gluconate supplement it should be used in those cases where the iron requirements exceed that which can be delivered by flourish at the recommended dose or signs of iron deficiency appear such as short and slender stems or yellowing between veinsr plants are able to much more easily derive a benefit from flourish iron than from edta iron sources because all edta iron is in the ferric fe3 state since plants r