Robert,

Whether your leach field has sat long enough to be a good filter again
really depends on the soil conditions and the amount of rain that you've
had. So no one here can give you a good answer. Talk to the local septic
guy, the local ag extension guy, the county health guy, et c. Do not tell
these folks that you think your system is failing. Remember that if your
septic system had multiple problems a rejuvenated leach field does not mean
that the system will still work.
You mention pumping and cleaning your "pit" but do not explain why it
needed this or how this was supposed to rejuvenate it. Since it needs it
again you may be dumping solids into the pit which means that you are not
pumping your septic tank enough or the chemicals did not do a good job of
rejuvenating the soil.

Dave M.