Submerged filter suggestions for 20 gallon long?

I'm currently working on switching from a 24 gallon cube tank to a 20 gallon long. The current tank houses 5 peppered corys (I'll add in two more after the move) and a nerite, and I plan to add in a betta in the future. My old tank also has the filter built in the back, so I need to transfer the filter media to the new filter.

I've been looking at filters for the new tank and, so far, this is the one that had caught my eye. I thought it would be a good idea to get a second opinion before making a purchase.

 

Haven't really used internal filters like that but Fluval seems like a good place to start.

 

I have a few of the Fluval U3 U4 and U 2 . The U2 is tiny . It’s an expensive pump with little room for media in my opinion.
All of the U series filters have a poorly designed bracket that clips on to them . The bracket holds the suckers. I have had a few small fish get stuck around the bracket and be unable to swim out. You can’t easily see them until you clean the filter..
In Australia all Fluval products are extremely over priced.

Regardless of the money they are sold for in your town it’s to small in the media department. Yes they work ok without the bracket just sitting on the substrate. I would suggest a U3 if you decide to get one?

 

Fluval is a great brand, so I'd usually start there when looking for new/unfamiliar products, personally.

If you're near a Petsmart, the Top Fin brand internal filters are actually really good. They're lower-flow, but come with sponges rather than cartridges (although they do consider the media disposible, there's no reason to dispose of it - it's just normal media), and can easily be filled with carbon or cycled media. I use them in QT tanks, hospital tanks, and displays where I'd rather not see bubbles from a sponge filter.

Top Fin® Multi-Stage Internal Filter | fish Filters | PetSmart

 

I have a few of the Fluval U3 U4 and U 2 . The U2 is tiny . It’s an expensive pump with little room for media in my opinion.
All of the U series filters have a poorly designed bracket that clips on to them . The bracket holds the suckers. I have had a few small fish get stuck around the bracket and be unable to swim out. You can’t easily see them until you clean the filter..
In Australia all Fluval products are extremely over priced.

Regardless of the money they are sold for in your town it’s to small in the media department. Yes they work ok without the bracket just sitting on the substrate. I would suggest a U3 if you decide to get one?

Oh dear, that doesn't sound good, I don't want anyone getting stuck, especially the future betta! Guess I'll keep browsing for other internal filters.
Honestly, after looking around some more, I feel like a sponge filter seems like it would be a good option as well. Any second thoughts?

 

I agree with flyfisha. I have several fluval internals and have experienced fish getting stuck between the filter and bracket (none the size of a betta though). It’s a rare occurrence but can happen - stuffing filter floss behind the filter can stop it happening. Otherwise, they run quiet and perform well.

They are quite bulky though and take up some room in the tank - any reason you want an internal rather than a HOB?

 

I like the Aqueon quitflow. It's all black and slim so it's more descrete. Only a small amount of sponge though and no room for other media. I use it when I have to set up a QT or other temporary housing.

 

I agree with flyfisha. I have several fluval internals and have experienced fish getting stuck between the filter and bracket (none the size of a betta though). It’s a rare occurrence but can happen - stuffing filter floss behind the filter can stop it happening. Otherwise, they run quiet and perform well.

They are quite bulky though and take up some room in the tank - any reason you want an internal rather than a HOB?

I have my tank in my room and I feel like a HOB would be noisier than my current filter and will keep me awake. Though I may consider getting a HOB if I can find one that's quiet. I've considered the seachem tidal but I've read the impeller is a pain to get to.

 

I have my tank in my room and I feel like a HOB would be noisier than my current filter and will keep me awake. Though I may consider getting a HOB if I can find one that's quiet. I've considered the seachem tidal but I've read the impeller is a pain to get to.

No more painful than an internal fluval…I have only used the tidal 35 and it is silent.

 

If you run a sponge filter you may have to listen to the sound of the air pump. To be perfectly honest I don't hear my HOB filters. They are so quiet I find myself checking to make sure they are running. The only time I hear them is during a water change and experience the waterfall sound. I keep my tanks filled all the way up and this prevents the waterfall effect.

I run penn-plax Cascade 300's on my tanks. 2 on my 55 and 1 on my 5.5 gallon. Actually over kill on the 5.5 but I had an extra one so decided to use it when the original filter failed. I have it turned down. We can never have too much filtration for our tank. We can have too much water movement if it affects our fishes ability to swim but never too much filtration.

Since you are in the market for a filter give some thoughts to getting a filter rated for a much bigger tank than you have. Filters are highly over rated as to their effectiveness so consider a filter rated for a tank at the very least twice as big as what you have. Even three times would not be too much.

 

If you run a sponge filter you may have to listen to the sound of the air pump. To be perfectly honest I don't hear my HOB filters. They are so quiet I find myself checking to make sure they are running. The only time I hear them is during a water change and experience the waterfall sound. I keep my tanks filled all the way up and this prevents the waterfall effect.

I run penn-plax Cascade 300's on my tanks. 2 on my 55 and 1 on my 5.5 gallon. Actually over kill on the 5.5 but I had an extra one so decided to use it when the original filter failed. I have it turned down. We can never have too much filtration for our tank. We can have too much water movement if it affects our fishes ability to swim but never too much filtration.

Since you are in the market for a filter give some thoughts to getting a filter rated for a much bigger tank than you have. Filters are highly over rated as to their effectiveness so consider a filter rated for a tank at the very least twice as big as what you have. Even three times would not be too much.

Okay, that actually makes a lot of sense. So I think I might settle with the seachem tidal meant for 110 gallons. I know it's more expensive, but if there's one thing I've learned from this hobby, you usually get what you pay for. Luckily I got an Amazon gift card for Christmas so that should cover a good portion of the cost.

 

Have you thought of a good old fashioned sponge filter or even better The Ziss bubble? the 200 L shallow version would be good for a 20. If you’ve got a few weeks you could just pop one of those filters in your existing tank and let them cycle.

I had a Fluval U that came supplied with a tank, and I really didn’t like it. It’s obviously well made as all the Fluval stuff is, but they’re pretty pointless IMO. It would cost you an absolute fortune to keep replacing the cartridges, obviously you could cut your own foam and use that but’s still hassle, and obviously maintainence on an internal filter is a bit of a pain in general. Other then the rip off cartridges there’s really not a lot of room for media in those filters. It will obviously do the job, but no better then a small sponge filter. The big drawback to a sponge or Ziss filter is that they take up tank space, but so would any internal, and what I like about the Ziss especially is that it’s pretty much maintenance free, and would likely have much more bio capacity then the Fluval U filter. Also if you plan to add a Betta, a sponge or Ziss (air driven) would be much better then the Fluval internal, as I remember my Betta struggled with the flow even on the gentle setting with the Fluval U3. Just my opinion from experience of course.