2 filters better than one...just in case...I don't know anything about the brand you're getting though but if jappy says good enough for the load then good enough for me...built in redundancy is always a good idea imo though so I would add another.
My preference would be two, but that's because I believe in backup, in case one filter fails when the pet store is closed. (Which, by a law of the universe, is always when that happens. :mad2
If you don't want two HOB filters, a canister would make a nice complement to the AC110 you already have. :idea:
well let me tell you the full story.....right now my 55 has an AC 70 but only about 5 small cichlids....... i will be adding about 8-10 more and i found the AC 110 for $45 each so i was going to get 1 (or 2) for my 55 and use the AC 70 on my planted tank....so every one thinks i should go ahead and spring for 2? or skip them all together and go for a canister? anything good in about the same price range?