This is a new term to me, the feet of seepage left. I assume that this means that the water is within two feet of the top of the pit. I will assume that this is the case. If this is not, please call me to discuss your situation. 

A seepage pit, like a drainfield, should remain essentially dry. There should not be standing water in it. The treatment of a pit is more difficult, but we have had good results using the following method. 

Have the pit pumped. Use a pole or a long rod to agitate the bottom of the pit. This breaks up the anaerobic crust that has formed and allows the Septic Scrub to penetrate and react with the crust from both sides. Add two bottles of Septic Scrub while the pit is still empty. If there is not enough water to dissolve the product, add some from a hose. Add two more bottles the next day and dissolve also. This should restore drainage to the pit. Watch the pit and if water starts to treise again, add two more bottles before it rises very mush. I generally recommend watching the pit for six months or so. The pit should remain essentially dry if it is draining properly. This assumes that you have access to your pit. If you do not, the treatment is less likely to be successful.

If you have any questions, please do not hesitate to call.