Red Spider Mites

What you probably are seeing is and outdoor critter called a Clover Mite. They are coming from the lawn/flowerbeds. When conditions are right the population will explode and will find their way inside. If you have not seen anything lately there probably is no need to do anything else. Any general yard spray around the lawn/foundation of the house will help reduce the numbers when they return. A non chemical way to fight them is to have a three foot band around the the house with no lawn/overcrowded flower beds. Rock mulch or bare soil with limited plantings in it. The foggers you used are only a contact product, so if there is a population in the walls you may have some return. Once again any general inseticide labeled for indoor use placed along the baseboards and window sills in the trouble area will help. Lar