as a dedicated Eheim user I would never touch an fx5, heard too many horror stories about them.
I only trust what works. I don't like the newer Eheims with their pointless electronics etc. .
A canister filter should be designed like the following:
1) inlet at the bottom
2) outlet at the top
3) high quality pump to run it
any other fancy stuff or silly buckets/chambers would put me off.
I would recommend Eheim 2260 without hesitation if you want a large fast filter. I don't care for the 2078 or 2080, just extraneous rubbish that they put on to go with the times.
If you want more flow out of a 2260 you can always change the pump and/or make a remote hose connection arrangement, you have to take it apart to do this, but it can be done and that's one of the nice things about them. I'm in the process of moving a 2260 to filter a 270 litre tank, will make a vast improvement from the 2 x 2217 that were running.
The other thing when talking about flow rate is that Eheim judge what they see fit as regards flow rate/canister volume ratio. They probably could make faster flows for the canisters but it's a change that they're unwilling to do since it would have manufacturing implications.
As far as value for money and reliability goes the 2260 is it. Period.
One reason the FX5 is noisy is specifically because of it's higher flowrate. It's difficult to design a quiet, high capacity filter. I understand that, but when I see this electronic trickery on the new filters it tells me they have decided that it's easier to turn the filter into a gadget showcase instead of spending resources on solving the more difficult problem of filter throughput.
The fx5 is not noisy because of high flow rate. It's noisy because it uses a lower quality motor, coupled with the demands to run at a higher flow rate.
Flow rate is not a difficult problem at all. Deltec HLP pumps are monsters when it comes to flow rate, you can attach one to a 2260 canister and you'll have something very fast and dead quiet, the only problem is cost.
From the looks of it Eheim does not feel the need to increase their filter's output to keep up with user's expectation and/or what our practices are now (remember these filters have been around for a long time, and hence we're made to spec according to old fashioned ways of thinking). "filter throughput" is not a difficult problem, convincing Eheim to address it IS.
