We just bought a house with a drywell for the laundry and it was overflowwing. We openned it up, took out most of the water and found the grey sludge at the bottom and many of the drain holes clogged. We tried breaking it up, soap digester and muriatic acid, and nothing worked. We have come to the conclusion that we have to build a new larger one to avoid many future problems. Can you tell me how to build one and how big to build it?