Seachem's Flourish Iron is composed only of iron gluconate which is shown to be readily absorbed and used by plants. Brightwell's product also contains iron EDTA, which is less available to plants in an alkaline environment.ive heard that seachems products are better...but i usually take that with a grain of salt. one person i talked to was super passionate about using flourish iron over the brightwell iron product. something about how the form that the iron is in...the plants have a harder time using the iron in the brightwell product. its over my head, so instead of trying to understand it i took the lazy approach and just bought the flourish iron.
The EDTA form of the iron takes longer to be used up so it provides a more stable supply of iron or at least that's Brightwell's philosophy from what I read on their website. The ferrous gluconate is absorbed by the plants very readily.so if my ph is acidic is there a difference or is alkalinity different than what I'm thinking?