We do the 40b with a 29g sump personally I'd never run a reef without one. Additional water volume helps with stability,have place for a good skimmer and equipment. Also gives a fuge area for lr rubble and macro for pods to thrive n export nutrients. Ours is reef ready and previously we used a hob overflow box on nondrilled tanks. So no help as far as drilling goes. We just used a petco dollar a gallon tank n got baffles cut at Lowe's we siliconed into place. Petco has another dollar a gallon sale starting Sunday. Hope this helps.
