Hang on or diy canister?

[Hairy_Harold]

At the moment I have a 50 Litre tank with a 500Lph internal filter with some fillter wool added inside it for a lil extra finer filtration (obviously it has flow control). There is only 1 fish in there at the moment murray cod (native australian fish) and will be adding a 2 eel tail catfish (another native australian fish). I am looking at adding some biological filtration by either a diy mini canister or a 250lph hang on, as daily water changes for safety suck. Am I right in thinking the diy would be better because I can find as big a container as I want and add more bio filtration then a hang on filter could ever offer?

 

[marchmaxima]

There are some pretty ;arge HOB filters nowadays and for a 50 L you'll probably find one that's more than adequate. But you are right in saying that you can adopt any sized container as a DIY canister. And if you want to make it larger at any point then you will have that flexibility where you won't with a HOB.

And I would go with as much filtration as you can. The murray cod is one big fish! I also advise you to looking at upgrading your tank. Murray cod can grow to 3 feet.

 

[jsoong]

50 l (12 gal) tank is not that big, so I am not sure how much mileage you will get with just upping the size of your filter. Generally, a wet/dry filter with a sump is the easiest way to increase the circulating volume of your tank. This is easier to DIY than a canister since it is not pressurized & doesn't need to be totally sealed. However, most people have sumps for much larger tanks. <Although a standard HOB filter can be thought of as a tiny above tank sump ...>

 

[Hairy_Harold]

I didn't really see it as too much work, being that's they have a silcone o-ring and locking clips on all 4 sides. That and a bit of silcone and it's sealed. I was thinking of maybe just attaching a hose to the outlet of an internal filter and having it pump water through the container instead of having an internal pump. That way the container can solely contain bio noodles and have the need for less holes. It's on the back burner for the moment anyway as i'm in need of a few more tanks to seperate some fish.

 

[jsoong]

Conceptually, a canister is really quite simple, but it might be hard to get a good seal under pressure. Most DIY canisters I've seen (on the web) started with some kind of sealed container, like this one:
DIY Canister Filter

I did remember reading about one made out of a garbage can, but I can't find the link ATM.