# Recommended HOB for 2.5gal Tank?



## theatermusic87 (Jun 22, 2014)

Not sure about that particular filter, however I have it's slightly bigger brother 
Deep Blue 10 Gallon mounted on the long side of a 5g and am quite happy with it, been using it over a year and besides a couple cleanings it works great. I'm using filter floss as the only media in it, and a piece of panty hose over the intake to keep the shrimp out, I have it throttled back just a little bit but it is more than adequate.

I also had it on a 3g halfmoon tank originally and again besides throttling it back a bit more it worked great.

My only complaint is that the filter box edges are not straight (at least on mine which is an older model), they are intentionally wavy, which while it might look better, makes it more of a challenge to clamp a light to it


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## Coralbandit (Feb 25, 2013)

Azoo and truaqua make mini HOBs ranging from 16gph -too much for you.
Most of the filters are in the $12-$18 range I believe.
Lots of betta keepers use the Azoo palm?
SunSun makes mini canisters also!
sunsun 602B(table top canister $25).


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## kruzerman (May 24, 2012)

I am using the Deep Blue HOB listed in the original post which is the same as the Azoo palm. This is on a 8" cube which is about 2.5 gal. There is a little flow but not too much for my betta.


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## Beardie (Sep 8, 2013)

This blows any hob out of the water imo

http://www.drsfostersmith.com/product/prod_display.cfm?c=3578+3579+3580+16742&pcatid=16742


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## kman (Dec 11, 2013)

Beardie said:


> This blows any hob out of the water imo
> 
> http://www.drsfostersmith.com/product/prod_display.cfm?c=3578+3579+3580+16742&pcatid=16742


That's pretty cool.  Easily the smallest one I've seen yet!


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## dru (Mar 9, 2013)

goodbytes said:


> I was thinking about one of these. They're only 16gph with adjustable flow so it should be nice and gentle current for the Betta.
> Amazon.com : Deep Blue Professional ADB88700 Biomaxx Nano Filter for Aquarium : Pet Supplies


I have a couple of these

The space for the filter media is tiny and they only come with two sponges. If you wanted to only run sponges for the media with no chemical filtration they will do. Or if you want to add some carbon to the media area these will fit:

Amazon.com : Lee`s Aquarium Disposable Carbon Cartridge Undergravel : Aquarium Filter Accessories : Pet Supplies


If you want to run Purigen the media area isn't big enough for even the smallest bag. Also, and this is with any HOB filter, the return flow will dump straight onto your substrate which may disrupt your scape. 

A better option if you intend to only run the sponge media is the Hagen mini elite. This filter can be tucked away behind plants and it does a surprisingly good job on a small tank for water movement and some mechanical filtration. Only downside here is for a betta the flow might be too high. Depends on the betta. 

If you want to run chemical filtration and have options on your return flow your could get a canister filter. I like the ZooMed 501 personally


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## kman (Dec 11, 2013)

ZooMed 501 and Finnex PX360 are the best small canisters, although the Rapids Mini linked above looks interesting. I've had great performance from my Finnex but the flow may too strong for a betta in such a small tank.

One option is for just a good HOB like the AC20, and baffle the output. Lots of DIY options to do this.


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## yellabelly (Mar 24, 2014)

*deep blue...*

You people are mentioning canister filters for a 2.5 gallon betta tank? Purigen? Ac20? OVERKILL!!!

The deep blue filter you mentioned is made for 2.5 gallons so WHY would anyone think it wouldnt work? 
I love my little deep blue. Only possible issue is with having a betta, the water level should be a little lower so they dont jump out (happened to my wifes). The filter ofcourse has a minimum level mark on the side but with 1.5 inches low in MY tank, its constantly at or just below the mark but i haven't had issues.
AND, not that it would be full blast but if it is, the filtered water comes out past the lip and flows right back down to the intake. I fixed this on my 5gal with a clear coke bottle piece folded over the rim under the outake to add a bigger lip which makes the water flow to the front and around and its not noticed by anyone but me.
Good luck!
It really is the perfect filter for 2.5 gallons and is almost half the cost of the IDENTICAL Azoo. 
Canister filters for 2.5 gallon.... ahahahahhababababababa


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## kman (Dec 11, 2013)

This is TPT. People live for overkill, here. LOL


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## dru (Mar 9, 2013)

A canister filter isn't some magical device that can only run on big tanks. It would just provide more options (media / intake / outflow) than a tiny HOB filter, and would extend time between maintenance. 

The Deep Blue sponges that come with that filter are ~1"x3" so you would need to rinse them weekly. If you don't, the water from the intake just passes right over the top of them. It is really a design flaw of these HOB filters. At least for the AQ20 you can be sure the water passes through all stages of the media. 

Increased surface area for biological filtration is also an important point to consider in a nano tank. For a betta it isn't paramount but if you care about keeping healthy fish it should at least be a factor.


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## goodbytes (Aug 18, 2014)

Thanks everyone for all the input, its really been helpful. To hear that people are using these tiny things with success is itself useful versus the possibility that these little HOBs are just garbage. Those mini-canisters are really neat but I can't imagine using one on anything less than five gallons, I mean looking at this 2.5 gallon tank the thing is almost toy-sized. I had seen the Azoo mini HOBs but the design seems identical to the DeepBlue almost as if they're all built by the same firm and just packaged differently. The media is a concern but I'll probably just end up going with custom media of my choosing anyway based on what I can cut to fit in there--maybe even just a single layer of good quality sponge. I only need this filter to support a single Betta and a couple of Nerites and it sounds like it'll do the job.


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## kman (Dec 11, 2013)

FWIW, I DO have an AC20 on a 2.5 gal tank. But (a) I don't keep a betta in there, and (b) it's a hospital tank so good circulation is important.

But, if I was to baffle the output (there are many easy designs), I see no reason why I couldn't use it as a full time tank, if I wanted. And yet still keep the far superior filtration offered by the AC20's design.


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## AGUILAR3 (Jun 22, 2013)

My LFS has maybe 10 2.5 shrimp tanks and all have an Azoo palm/mignon 60 mini HOB and the output water is barely trickling out. Perfect for a betta


http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=9821


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## inthepacific (Oct 21, 2012)

the zoomed canister is a good option too. i have it and the outflow isn't that strong at all. I ran it on a bare bottom tank which i disturbed so all the debris was floating around the column. Zoomed canister cleared it up in about 2 minutes while the flow was still calm. I'd recommend it for tanks smaller than 5 gallons


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## TheGreenWizard (Jan 19, 2015)

The Azoo Palm Mignon 60 is great - I have it on a 1.9 gallon Hex tank now, with only the sponge, and the water flow turned to the lowest level. So far, the betta in there loves it!


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## retrocity (Apr 18, 2011)

I have the Deep Blue Nano on a 3G Betta tank with no complaints. It provides just enough movement that it doesn't bother my Betta (I keep it turned about halfway). I keep some ceramic rings from a fluval filter in there and might add some purigen as well.


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## Beer (Feb 1, 2012)

I have a few of the Deep Blue nano filters. They run great and are fairly quiet. The surface area of the sponges are sufficient for a 2.5 gallon Betta tank with the stocking you are talking about, especially if is modearately planted. Filtration really isn't necessary if the tank is planted. With a tank that small and stocked that light, why would you have the need for purigen or other chemical filtration? A water change somewhere near 100% can be performed fairly effortlessly, a couple if you messed something up pretty bad.
The only time I had issues with those filters was when I ended up going over a month without a water change. The cover is clear, so if your light is over the filter, you can start to grow algae on the top of te sponge, which can be a pain to remove.


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## bobfig (Aug 30, 2014)

my betta has been doing fine in his 2-2.5gal cube with a zoomed 501 filter for over 2 months. he has made at least 3 bubble nests in there. i just leave the 90º on the out put with the little clip on thing and point it in to the corner where the heater is. i did however use some eheim substrat pro in it and use some poly fiber with a course sponge in it and not like how they want it set up.


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## dru (Mar 9, 2013)

Beer said:


> With a tank that small and stocked that light, why would you have the need for purigen or other chemical filtration?


Driftwood that leeches tanins (and has for over a year) 

Doing 100% water changes every 3 days isn't ideal


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## Beer (Feb 1, 2012)

Okay, under normal circumstances I wouldn't have seen a need for that, but if the driftwood is still did coloring the water and pulling your pH down, then I guess it is warranted.

I forgot about the last time I set up a tank with driftwood. I boiled it at least a dozen times and soaked that thing for weeks with multiple daily water changes and it still stained the water for several months.


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## jarjarstinks (Feb 14, 2015)

+1 on the Azoo Mignon 60. I use one on a 2.5 gallon low tech tank.
Amazon.com : AZOO Mignon Filter 60 : Aquarium Filters : Pet Supplies


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