Ferrous Sulfate Questions

[Left C]

I have about one pound of ferrous sulfate. It is light green in color and it has an almost sandy, powdery consistency. I do not know if it is anhydrous or one of the hydrated forms. It is simply labeled 'Ferrous Sulfate.'

Is it possible that it can be used a substrate amendment or for dosing iron? If so, how much? Will it kill aquarium mosses and fissidens at this concentration? Wikipedia says: "In horticulture it is used for treating iron chlorosis. Although not as rapid-acting as iron chelate, its effects are longer-lasting. It can be mixed with compost and dug into to the soil to create a store which can last for years. It is also used as a lawn conditioner, and moss killer. All iron sulfates dissolve in water to give the same aquo complex [Fe(H[SUB]2[/SUB]O)[SUB]6[/SUB]][SUP]2+[/SUP]." Ferrous sulfate monohydrate is used in such moss killer products as Scotts Moss Control and Ortho Moss-B-Gon.
http://en.wikipedia.org/wiki/Iron(II)_sulfate
http://gardening.wsu.edu/library/lawn003/lawn003.htm
http://bryophytes.science.oregonstate.edu/page22.htm

 

[Biollante]

Definitely Not the Monohydrate


Hi Left C,

If it is green or bluish-green it is the heptahydrate (*7H2O). I guess you can get the tetrahydrate (*4H2O) by heating, don’t know why you would want to, it wouldn’t be the nice green anymore.



Iron sulfate can be used in aquariums; it is not as fast acting,it releases iron in a plant friendly form over time, complexed by biological action.


As long as you used the iron sulfate as you would any other, you should be okay. I think one of the articles you referenced said if using in the substrate, use 2% by weight, which sounds about right.

If you wanted to use it the aquarium, mix up a 10% solution, then dose as you would any other 10% iron solution. I do not think it will be as effective as chelated forms, but it also won’t be an herbicide either.


If you have some chelate, EDTA, DTPA, Vitamin C, what have you that can help.



Biollante

 

[Left C]

Thanks a bunch, Biollante. I've had this ferrous sulfate for a few years, but I shunned using it. It is good to know that it is heptahydrate. I can do the math now to make some solutions. The herbicide part threw me a curve. I was sure that it was the very high concentrations when it acted as a herbacide, I just didn't know how low of a concentration to make. Now I can make one because of your help. I have over a pound of it and I wanted to use it. It should last a long time. I'm going to add some of it to the substrate in a new tank like you mentioned. I'll have to pick up a chelate product.

Thanks a bunch for your advice. I really appreciate it.