I'be been running Eheims for over 3 decades. In my experience they are rather optimistic with their ratings. German hobby standard and Eheim's heritage are planted, lightly stocked small community fish tanks... and then the rating might apply.
Having said that, I am a strong believer in long service intervals. If I need to clean a filter every couple of months I consider it underperforming. A true biofilter should effectively degrade biomatter, not just trap it and clog up...Just my $0.02
Actually, Eheim now publishes ranges - the 2215 is rated from 32-92 gals, the 2013 from 21-66 gals.
But honestly, what matters at the end is that it supports your specific tank, which hopefully is now the case with the addition of the 2013. jryegolds, what's in your tank? Care to share a full tank shot? We love pics here!
HarleyK
I tend to agree with you HarleyK (I've been using them about that long but not consistently so don't consider myself in anyway an expert). In all the talk of having 3 FX6's on a 10g guppy tank these days I kind of get lost. I think what jryegolds said about doubling it is about right for me. FWIW, on my upcoming 175 gallon I've about decided to go with 2x2075's with powerbeads for movement (but the 2262 is still calling out to me).
(*By looking at threads from HarleyK, I decided not to spend so much money on a 2080)





