Looks nice, did you have any issues with algea on the bottomMy first tank has Sand.
My new (~2 weeks old) tank is BB, I went with BB because I don't clean sand and for less maintenance overall.
I got a grey (non colored) PVC sheet on the bottom and for Biofiltration I threw about 20 liters of Sera Siporax (which I had lying around) into the sump.
I hope it works out well
Picture from ~2 weeks ago, as I first filled it up: