If your leach-field is saturated because of the heavy rains you might well consider a pump out.
Look into to new mound system for your leach-bed area.
I,m looking into some investment property so I,ve been studying poo disposal online.DO NOT dump drain cleaner in your tank.You will destroy the sewage decomposing ability of the bacteria.
Are there too many trees(roots) in your leach-field?
Is your tank the old single vault type,not a double vault?