I made a big batch of DIY rock from directions I got from ou812pezz. I made ~160lbs for under $40 in materials. If you got the time (2.5 months), then you will come out ahead on the deal ;) I still got plenty of time building my system so this is an option I can try in the mean time. Plan is to make enough base rock and then cover it with live rock ontop. It just takes a long time because youhave to soak the DIY concrete rock in fresh water to bring to the pH level down. Then a few weeks of curing it in saltwater with some live rock.

If you got any questions ask the two fellas Tater mentioned above :lol They have more experience in it I'm sure. But I'll answer any questions you got. Or if you wanna swing on by the casa one night that could work too.