Hoppy,

I agree with you that the ammonia levels we are dealing with are extremely low. However, i don't feel that these low levels are only signifigant at the substrate. If i remove the ammonia in the column with zeolite, the concentration gradient created should "pull" it out of the substrate. That being said, this is far from an excuse to avoid siphoning out detritus and dead plant material.

I can see that a tank with healthy plants is more than capable of dealing with the average ammonia production. In my case, even though my tank is established it might still benefit from a period of carbon and zeolite from what im hearing here.

Thanks for all your help!