When googling Rena Smartfilter 55 problems, I do see that there has been a history of noise with it. The filter is the closest to a canister filter there is of all the HOB's out there, you might want to consider switching to a canister filter. Perhaps look for a used one in your local area (Craig's list?). Locally where I live I'm continually seeing used filters for sale. In fact I purchased a used Acquaclear 30 as a back up filter, seed filter and quarantine filter to be used with my Eheim 2232 on my 20 gallon tank.
Product Description: Rena Smartfilter 30
The only thing I can think of is they don't like the strong current from the HOB filters. I have a Rena Smartfilter 55 and Rena Smartfilter 30. The reason I believe this is because the power was out and I noticed the guys come out of their hiding spot and swim around. They don't do this when the lights go out at night, so I'm guessing it's the current.
I have a Rena Smartfilter 55 and Rena Smartfilter 30
Alright first off, do not expect this as regular quality, it is with my new camera, but one I did not load in HD and I messed up when I shot this and uploaded to my computer so the quality will be better than this. I just have to read the 1000 page manual for my camera, its my first advanced camcorder so, might take a few tries.
Anyways, the filter in this one is the Petco65. These filters are off-sets or clones of the Penn Plax Cascade hang on back power filter series. Its actually a pretty nice filter, theres only a few filters that I would even think about before this one and I will list those further down. This filter has 3 layers though I would not depend on the "Bio-Falls" (last 3rd layer) as it is really just a piece of plastic impeding the flow though I imagine it has some effect and works better than Aqueons version. In order the layers are : carbon/paded cartridge, "Bio Sponges", and "Bio-Falls". This filter is also very quiet and so is the output of water. Now I wont really go into further detail here as you can just watch but, I have found it reliable, though I do wish it had a higher flow, this is defiantly not suited for a 65 gallon tank as it says. They over estimate it as do all manufacturers, id say it would be good standing alone for 30 gallons or less.
Now im not saying this filter is the best in anyway I am just saying its a good one compared to most. Hang on Back power filters I would take or are better than this one would be : AquaClears, Fluval C series, Rena SmartFilter, Marineland's (this is up for debate im not sure), and Via Aqua Vitalife's (this one is up in the air). Now that list is not limited to whats on there those are just some off the top of my head.
So as you can see this isnt quite your normal single cartridge system and really just pushes those systems over. Theres so many of those types im not even going to list them but I think I mention a few in the video.
Hope this helps, if you have questions let me know.
Thanks for tuning in!
Rena SmartFilter 55, UP TO 55 Gallons · AquaTechPower Filter 30-60 ..