How often do you clean and how thorough a cleaning do you do?
Have 2 Eheims 2217's for a 125 gal. It's 2 months old and a lot of diatoms, etc. have gone into them.
Hoses are full of bacteria (crud?) and suspect everything should be cleaned, while adding new beneficial bacteria. Actually, clean one and do the other a month from then.
unless you see a pretty large change in your flow, or dont feel the filter is doing its job well there really is no reason to mess with things. i have a rena xp3 on a 55g and have cleaned it 2x in a year and 3 months, and everything is great.
I have found the frequency of filter cleaning for me is highly dependent on how much fish food they eat. I just cleaned 2 Fluvals that lasted over a year, the rest of my Fluvals usually go 4 or 5 months. My eheims get cleaned more frequently, rarely get one to last 4 months. Flow gets kinda tricky sometimes, after a while you get a feel for the filter and how it performs for a certain tank. I would think two 2217s would last 2 or 3 months at least on a 125, again depending on how much fish food they eat and of course the bio load.......DC