I wanted to know if aluminium and iron oxide could be nutrients for my producer, as such I went to research on them. Here's is what I found about their effects on plants (the Earth producer).
Aluminium
Aluminium is primary among the factors that reduce plant growth on acid soils. Although it is generally harmless to plant growth in pH-neutral soils, the concentration in acid soils of toxic Al3+ cations increases and disturbs root growth and function.
Taken from: http://en.wikipedia.org/wiki/Aluminium#Effect_on_plants
Iron Oxide (rust)
Green plants apply iron for energy transformation processes. Plants that are applied as animal feed may contain up to 1000 ppm of iron, but this amount is much lower in plants applied for human consumption. Generally plants contain between 20 and 300 ppm iron (dry mass), but lichens may consist up to 5.5% of iron. When soils contain little iron, or little water soluble iron, plants may experience growth problems.
Taken from: http://www.lenntech.com/periodic/water/iron/iron-and-water.htm
If so, Aluminium will not be good choice for nutrients and rather, should be avoided. Iron oxide, however, would be a good source of nutrition for my organism.
