Smallest HOB filter?
 

Hey guys, I built a 5 gal DIY tank for a specific application, and there is only a 4" space in the back for a HOB filter. The only filter I could find that would fit is the Red Sea Nano Filter. I've been building this tank for 2 years and between the time that I bought the Red Sea Nano Filter and the present, it has stopped working (which is odd, since I used it once to check that it worked, and then put it back in the box). So before buying another one so prone to failure, I thought I'd ask if any of you knew of any small(er) HOB filters?

The Red Sea Nano Filter was only recommended for 3gal tanks, whereas mine is a 5gal. I added a DIY sponge filter to supplement the HOB, but I have no idea what its filtering capacity is. Kind of OT, but any idea how to check the flowrate/capacity of that sponge filter?

What are you going to be putting in the 5 gallon? More than likely you will be prefectly fine with a sponge filter. I have a diy sponge in my 5 gallon which I made from one of the filter replacements from the elite sponge filter, it is the smaller one that has a plastic box frame that sticks on to the glass. I made a hole into the sponge insert and placed my airline tubing into it. It has worked well for me.

Hahaha, that's very similar to what I did here!

I bought the single Hagen Elite Sponge Filter, was dissatisfied with the bubble size, and so I made my own from the pieces. Did you end up cutting the sponge, or using a shorter lift tube? My lift tube is about 6-8" (8 if you include the airstone).

I'll probably put in a few tetras or guppies, or maybe zebra danios- I'm really not sure at this point! I figure I need to let the aquarium cycle first before I even need to make a decision. Probably the tetras though (maybe 4 or 5 of them?). I might get a shrimp or two, too.

I always thought that the sponge filters were kinda sketchy, so I'm hesitant to use it as my primary filter. It'd sure be nice though...

With my diy sponge filter, very simple no lift tube. Have it in the tank with a betta and two mystery snails. Have had no problems with it. On all my other tanks I am also running sponge filters, in my 50 gallon I have two one in each corner. All the tanks are cycled other than my lastest 20 gallon grow out which I set up over the weekend. I have had no problems with my water parameters, and other than the 50 which is planted I make sure to vacuum the gravel well when doing water changes.

Hmm, how does that work with no lift tube? The bubbles go through the sponge, or what?

I guess I should be fine then with my 5 gal xD

Yes the bubbles come right through the sponge. Here is a couple of pictures.

All right, thanks! I'll try it out.

Your welcome and good luck, I orginally got the idea off of youtube, the person was using sponges that you would use for cleaning, but I wanted to make sure that what I used was definitly suitable for aquarium use. If I remember right it only cost me a few dollars for the sponge replacements, which came two in the package.