Welp, as always I've overspent on the startup of my new tank (540 gallon). One of the last expenditures I need to make is media. I have a 100 gallon Rubbermaid stock tank with three 32" filter socks then foam pads. Is spending $100 on a 5# bucket of Pond Matrix worth it or should I spend $5 on lava rock. I'd like to avoid pot scrubbers. Let me know what you think.