Substrate to fill 180 gallon


Reefing newb
I'm getting close to the point where I fill up my 180 gallon. I'm wondering about the substrate. I want to go sand and at the same time be economical about it. I'd like a deeper bed, maybe 4"-5". I was thinking I could fill about 3" with well-rinsed play sand then the top couple inches with something that's meant for a reef like oolite aragonite. Is this doable? I'd like fine sand so future gobies and such can make a home and do what they do. Also curious about black sand. I've never tried it but think it may look nice and be something different. How to fill a tank this large and still keep the cost down?
any sand you use must be silica free and you dont want really fine sad or your powerheads will blow it around and make a sand storm in your tank