The booklet for the sealed sump pump in a box was not left with me and I would like to know how to do monthly or yearly cleaning maintenance to it to avoid any odors that may arrise. The only waste water that goes to it is from the washer and I would like to know if there is any cleaning solution that can be poured directly down the laundry sink drain directly feeding the pump box? The system is installed properly and vented following all codes

Is this a sump or ejector pump? Do you put a nylon sock over the washer hose to filter about the lint before it enters the pit? There is no magic solution to clean out the pit. You'll have to get your hands dirty. Let me know what you have and well chat more, Tom

You can use bio-enzymes that are specifically made for this.