One thing you may want to check on the system is whether the lines going from the tank to the drains were sealed properly.
My brother just had a new raised septic system in, and within a few weeks, it was pouring out of all different sides and top of the mound. What was happening was that the installer did not seal the pipe connections and any and all rain that came down got directly into the tank and lines. Then, coming off the mound went right back into the lines again, a viscious cycle. This could be the problem you're having as well. You should not have to pump out your septic system for many years if it's working properly, and you stated you "suck it out" regularly which leads me to believe you're getting ground water into the tank and lines just as in my brother's case.
John
My brother just had a new raised septic system in, and within a few weeks, it was pouring out of all different sides and top of the mound. What was happening was that the installer did not seal the pipe connections and any and all rain that came down got directly into the tank and lines. Then, coming off the mound went right back into the lines again, a viscious cycle. This could be the problem you're having as well. You should not have to pump out your septic system for many years if it's working properly, and you stated you "suck it out" regularly which leads me to believe you're getting ground water into the tank and lines just as in my brother's case.
John