IMO the best HOB out there. I have and use 6 of them on my tanks. If you're using it in addition to your Eheim on your 55, you should have excellent filtration!
It would be in addition to a mechanical only ( Cartridge with filter floss) top fin 60 (300 GPH) And an eheim 2215 and an undergravel filter. If it is noisy though ill have to go another route like another 2215
Ok, so with my annal retaliation aside. These filtes are the best HOBs on the market. I personally loved them when I saw them. The only filter with 3 stage filtration, I only used mech. and bio. in mine. It worked fantastic on my 30 gallon tank for primary filtration. It does the job. Atleast untill it sucked up sand and that ended its use. Fluval 304 back on at that point. Then my sisters dog chewed up the basket so that ended its life. Now I might be able to use it as another form of filtration.
I wouldn't recommend it for primary filtration on a large tank. There is no reason why you can't buy a canister or build a wet/dry.
Canisters beat this filter hands down on mechanical filtration so recommending it as a secondary filter to a canister is a little absord I think. By another canister, I know its more money but you will get better filtration.
I've been using them since they were called AC500'S. The large rectangular media space makes them a DIY dream. I use usually double foam for maximum mechanical filtration.
To easily clean your foam blocks just take them outside and hose them out well with a spray nozzle. I have reused the blocks for years this way and it is a lot more effective than wringing them out under the tap (my other cleaning method).
another canister would definitely be a better choice, if you can afford it. if your just looking for something cheap and dont care about looks or anything, go with the ac110. if you add that to your tank you will have plenty of filtration. and you could even remove the topfin 60. if you wanted.
the ac110 is an OK filter. like i stated in your other thread, i have one. its pretty good as a secondary filter. its pretty quiet as well. but i would still reccomend another canister over it.
the ac110s are HUGE, i had to pull my tank out another 3 inches from the wall to add it.
nonetheless, im taking it off of my tank, but i will have it just incase something happens to my primary filtration.