Chelated Iron In Aquariums - DTPA, EDTA or EDDHA
IRON AN ESSENTIAL MICRONUTRIENT FOR AQUARIUM PLANTS ( CHEMICAL SYMBOL – Fe )
Optimal levels of iron (Fe): 0.2 – 1 ppm. It can be determined with a suitable water test. Iron is an essential micronutrient needed by all plants.
Deficiency of iron (Fe): causes less chlorophyll formation in plant’s new shoots. It can easily be identified at the shoot tips fading in colour. Iron deficiency can be seen first on fast growing plants. Iron deficiency can easily be corrected by adding iron fertilizer. Aquatic plants absorb iron very quickly. After few hours, iron might not be determinable anymore.
The best iron fertilizers are the chelate iron fertilizers. Chelates are the compounds that stabilize metal ions ( in this case - iron) and protect them from oxidation and precipitation. Different chelates ( EDTA, DTPA, EDDHA ) hold iron ions in different strengths at different pH levels. They also defer in their susceptibility to iron replacement by competitive ions. For example, at high concentrations, calcium or magnesium ions may replace the chelated metal ion. These chelated fertilizers also ensures that the iron is kept in ferrous state, plants absorb iron in ferrous state.
Fe-DTPA chelated 7% - DTPA is also used as a chelate for aquarium plant fertilizer, specifically iron, an essential micronutrient typically needed in substantial quantities by all plants. This iron chelate is effective up to pH levels 7.5 . This chelate has less affinity to calcium compared to EDTA chelate. Buy here premium grade of Fe-DTPA chelated 7%.
Fe-EDTA chelated 13% - Iron EDTA Chelated works best in aquariums where pH level is at 6.0 or lower (i.e. soft water tanks, soft water is low in minerals, usually low in pH). EDTA chelated iron typically has availability of several hours. Buy here premium grade of Fe-EDTA chelated 13%.
At pH above 6.5, nearly 50% of the iron is unavailable. Therefore, this chelate is less effective in alkaline water ( Hard water- high in minerals contents, largely calcium and magnesium carbonates, high pH). This chelate also has high affinity to calcium, so it is advised not to use it in calcium-rich water.
Fe-EDDHA - this chelate is stable at pH levels as high as 11.0, but it is also the most expensive iron chelate available. This chelate will colour your water for a while.