20g reef tank build

I'm new to TRT and this is my first saltwater tank. I'm currently thinking of running an hob overflow box with a 5.5g sump/refugium but this is what I have now. Tank is currently in diatom stage due to having the light on the wrong setting and full intensity. Any thoughts/positive comments are welcome.

20gal standard

Fluval 205 canister with live rubble

Aqueon 700gph circulation pump

24" current USA sattalite orbit

20lbs live sand

20lbs live rock

Fluval 200w heater.

Will post pics later. Thanks