How many gallons of bio balls?

[ek]

Hi! How many gallons of bio balls do I need for a 150gl tank with a 2000gph pump?

 

[mac]

The old rule of thumb is 1 to 1.5 gal. of bio/balls per 10 gallons of H20. But reading up on current set-ups, wet-dry bio filtration seems to be "old school" now; as DSB + LR moves to the forefront of the filtration standard.
Don't take me wrong, I'm still not converted to DSB either. Just something to think about.