Iron Sand to Remove Phosphates?

[AnotherGoldenTeapot]

Phosphate removing compounds, be they aluminium or iron based, are silly prices in New Zealand. For example, a 250gram container of Seachem's Phosguard costs about $40USD.

Interestingly the beaches on the west-coast of Auckland commonly have a sand that is coated in iron oxide (the sand is black and it's not a great idea to walk on it bare foot in summer).

The sand is free and available in infinite quantities. You can even buy it in 20Kg sacks for $1USD to save having to go to the beach. Some of the bagged sands claim to be 80% iron oxide (although those ones only come in 1000kg lots 8O).

Does anyone have ideas of why it would not been a good idea to use this iron-sand for phosphate removal?

 

[Acropora]

I would like to know also,so i'll give this a bump.Then it would make an excellant sand bed.

 

[GSchiemer]

The PO4-removing products are ferric oxide hydroxide, not iron oxide. You also have to be concerned about impurities, such as heavy metals, that might prove toxic to marine life. Doesn't sound like a good idea to me unless you can thoroughly test the product.