Seachem Flourish Iron is Highly concentrated (10,000 mg/L)
Ferrous gluconate iron in ferrous form
Ferrous gluconate is better suited to foliage feeding than iron-EDTA
Plants cannot divert iron from older leaves to new ones so this means that if you have an iron deficiency in your aquascaped aquarium it will first show on the leaves of new or young plants . Plants use iron to produce chlorophyll , a lack of iron will mean that young leaves start to turn yellow . Any new stems which appear may also be short and thin , if the iron deficiency continues over a period of time then each new leaf will have a lighter colour than previous leaves .
There are many iron supplements on the market and we will try and help you understand why Seachem Flourish Iron is one of the better ones . To help understand we need to explain the difference between the two oxidation states of iron :
Ferrous : +2 charge . This is the preferred iron form and is soluble in water at any pH
Ferric : +3 charge . This is only soluble below a pH of around 5.5 . Most planted aquariums will have a pH of over 5.5 and so this means the Ferric iron will become insoluble and settle in the root zone . At this stage the foliar absorption become impossible . Competing products using this type of iron employ a chelate of ferric iron which is called iron EDTA . This does keep the iron Ferric soluble but it has some drawbacks in relation to foliar update 1/ Iron EDTA bonding is strong and so very little of the iron is available to the plants 2 / energy must be used to extract the iron from the EDTA iron and then convert to Ferrous
Seachem Flourish iron makes this all very easy in that it uses a complex of ferrous iron and so plants do not need to use energy in extraction . Some people think that ferrous gluconate is harmful to plants but this simply isnt true , ferrous gluconate is better for plants that iron EDTA as it has a weaker iron - gluconate bonding .