OVAS

I bought a 75 Gallon tank.

I have lots of gravel from previous aquariums and have had much success growing plants but I was  thinking of experimenting with iron rich substrate, maybe clay covered by gravel.

Any ideas on this and is there a very cheap way to get this stuff since the price of laterite is crazy!

Thanks.

I have never used clay myself as a substrate, but I have read success stories form others so that I am considering it an option for one of my future setups. Kind of a black earth with a layer of red clay covered by normal gravel combination ...

Go with red clay because of its higher iron content. Pure red pottery clay works best. I got come once in a community center that offered pottery curses. A huge block was somewhat between $10 -20.

Thanks for the suggestion. I will look into getting a pottery clay block.