refugium size


Reefing newb
I have a 285 gallon with a 55 gallon sump with an asm skimmer gc-15 and a phosphate reactor. I am thinking about also putting in a refugium. What size would it need to be so it will be beneficial to my tank?
I was reading that a 6" sandbed in a bucket would handle a 100 gallon aquarium in Coral magazine. I am using a 1m x 1.5m sand bed on my 4000 litre runs.
Is there a size that is too small that will have little benefit, I might only be able to fit a 30 gallon.

You could always have one made of acrylic. I have a 70 gallon sump under the 85 and I'll probably add a second refugium for growing chaeto, caulerpa and dragon's tongue algaes.

If your DSB is trapping that much dirt reefnoob, you're doing it wrong. The water flow should be ripping over the top of that sand bed as to not allow it to settle in or into the sand bed.