building a sump...need some help

[sphelps]

OK here's the general layout done in CAD followed by the final product pictures. In the CAD drawing all features are not shown and I altered the final product slightly to accommodate for a higher flow rate. The basic dimensions are the same though. If you omit the water reservoir you'll end up with dimensions very close to what you're looking for (30x18x16). Also please note that this is purely for reference purposes only, not open to criticism and was designed for someone else. Your exact needs/wants will not necessarily match this exact model.