If you were to install an Air Flow Direction Panel you would find that all that straw and debri would be lifted up into your existing spreaders and they will do a great job. Without this installed the chaff and straw just fall out the back of your combine because there is not enough air being forced up and throughout the entire length of the sieve and that is the primary cause of your problems. With this increased air flow you will also find a much cleaner sample in your tank and a greatly reduced load on your return system.