4 Gallon Sump. Would it help?

[JimMelAddie]

There's a 4g sump on ebay:eBay: 4 gallon sump box ideal for wet dry filter (item 230086910101 end time Feb-08-07 19:32:23 PST)
I'm pretty sure this would fit in my stand, which I built rather narrow. Anyone think a 4g sump would be a decent wet/dry for a 40 gallon tank?

 

[JimMelAddie]

Correct me if I'm wrong, but the seller said it is 12" x 24" x 14". Therefore, that would mean it is actually about 15g, right? I should JUMP ALL OVER THIS, huh?