could I have naturally occurring GFO?

[ShannyG]

My water is mineral rich, especially in iron, all my toilets and bathtubs/sinks have rusty red staining. It is also very good for keeping things alive in, everything from fire bellied toads to pond koi and now saltwater aquaria. My pool also never turns green no matter how cavalier I am about chemicals.
I have learned that decent mechanical filtration will pull out the iron oxide particles. My pool filter turns rusty red, the Biomax in my aquarium
filter also becomes coated in the excess iron as my water clears. Could this be creating some sort of natural GFO reactor? I am a fan of frequent water changes so I would always be introducing a little fresh iron into my system.

[john08007]

I'm taking it that you do not have a RO filter? How are you preparing your saltwater?

[ShannyG]

No filter. I prepare my saltwater straight out of the tap.

[bertoni]

The iron might serve as a supplement, but I don't think there's going to be enough of it to adsorb a significant amount of phosphate, but it might act as a bit of flocculant, or it might not be doing anything at all. That's hard to determine. You'd need to run a number of experiments to see what's happening. I'll have to think a bit more.

[ShannyG]

My brand new 25g just cycled fully in a week and a half, and I was at a loss to explain that as well until I started thinking about the iron issue. I haven't opened up my filter to look at my Biomax but I am confident it would be rusty red in color.
Geez, maybe I can sell the plugged up filters out of my Brita on the interwebs as some sort of miraculous filter media????

[bertoni]

Well, they might start to act as a smaller-pore filter, to some degree. I wonder whether much phosphate would adsorb. I just don't know.

[Dan_P]

My water is mineral rich, especially in iron, all my toilets and bathtubs/sinks have rusty red staining. It is also very good for keeping things alive in, everything from fire bellied toads to pond koi and now saltwater aquaria. My pool also never turns green no matter how cavalier I am about chemicals.
I have learned that decent mechanical filtration will pull out the iron oxide particles. My pool filter turns rusty red, the Biomax in my aquarium
filter also becomes coated in the excess iron as my water clears. Could this be creating some sort of natural GFO reactor? I am a fan of frequent water changes so I would always be introducing a little fresh iron into my system.

The ratio of absorbed ortho phosphate to GFO is quite small, about 2.5 g to 1.0 kg. Free iron will precipitate quickly in salt water, making it unlikely that it will be around to precipitate iron phosphate. The amount of precipitated iron will be too low to remove phosphate.

You will also need to get a handle on the identity of other metals in your well so you don't poison your aquarium.

[outssider]

No filter. I prepare my saltwater straight out of the tap.

You know you have iron contamination but who knows what else is in the water. I hope you're not drinking this stuff !!:sad2:

You are really playing Russian roulette using that water in your tank...

[john08007]

You know you have iron contamination but who knows what else is in the water. I hope you're not drinking this stuff !!:sad2:

You are really playing Russian roulette using that water in your tank...

the idea made me cringe also, hopefully you are not in an area where they are doing any fracking

You can get a small RO set up pretty inexpensively now it's well worth the investment.

[billsreef]

You know you have iron contamination but who knows what else is in the water. I hope you're not drinking this stuff !!:sad2:

You are really playing Russian roulette using that water in your tank...

Iron is naturally present in ground water, it is not there as contamination.

As for ShannyG's question, another consideration is that in some areas that iron is already bound with phosphate and could actually be a phosphate source as a result.