DSB VS BIOBALLS

[MitchM]

The chaeto will help, definitely. The sand will be interesting to watch what develops.
You'll know that the sand bed is getting overwhelmed if detritus settles on it for any length of time (quick, like more than 1/2 hour).
Sand beds take a couple of months to develop before they can really start processing the waste.
If you're not placing any corals in there you could also incorporate some filter socks into your filter system.