12-09-2004, 06:46 AM
Join Date: Apr 2004
Location: Hibbing, Mn. USA
iTrader Positive Rating: 100%
Most of it depends on the load in your tank and the type of filter.
I usually do the back flush every 2 - 3 months and a tear-down every 6 months. I have never really noticed a slow in the water flow in the Eheims even after 6 months, so I just use the above schedule with good results.