Under Gravel Filters

[samiam9818]

I'm starting up a 40 gallon tank in about a week.
In my current 10 gallon I don't have an under gravel filter but should i get one since i'll have a larger tank?

What are the benefits to having one? What are some good brands?

Thanks!

 

[fatheadminnow]

Personally I would not get one as they take up Substrate space, and ultimately they decrease water volume.

Also, they are not that good for mechanical filtration.

I would just get a good HOB (Hang On Back) filter or canister filter.

-FHM

 

[Craster]

Undergravel filters are generally regarded as a maintenance nightmare and old technology that has been well superceded. There are still those who advocate their use, but not many.

 

[mixmaster jay]

i agree with fathead minnow they are not that good hog or external canister filter would be best mate

 

[samiam9818]

thanks!

 

[mixmaster jay]

no problem glad we could help

 

[meguro]

Could the reason why they're considered bad be expanded on please. As I've read that a lot but curious to know why.

 

[aaronnorth]

hard to keep clean, they keep getting blocked constantly due to the large waste and removing them for cleaning is near enough impossible!
Also, if you are going to keep plants then they are no good. The roots can block the filter holes, but also the filter can slow root growth. It pulls oxygenated water through which in turn keeps some nutrients locked up in the oxide precipitates such as iron will become iron oxide. Plants cannot use this.

 

[loachman]

Basically, they pull all the waste into the substrate and it will end up under the UG plates as well. It will clog up the intakes over time. As a result of all the junk in the substate, cleaning can be a HUGE pain in the... You've got to basically rip the tank apart to get all the waste out of it.

Canister filters are much easier to clean, and can use a wider range of filter media.

HOB filters are also decent for your size tank, not quite as efficient but not too expensive and simple. Again, these are very easy to keep free of detritus.

 

[meguro]

Thanks Aaron and loachman.

 

[rabbut]

Basically, due to maintenance. Contrary to popular belief, they are better than most at Mechanical and Biological filtration, due to the competitively fast filtration compared to other system, the massive filtration area (the whole tank footprint) and large media capacity. They are also dirt cheap to set-up. Considering their plus point, would I use one on my own system, no, probably not, for two key maintenance reasons...

The require 50% of the plate to be deeply gravel cleaned each week. Not too bad, usually you shallow clean the gravel weekly, but cover the whole lot... However, the real killer. The under-side of the plate clogs up with time, requiring you to completely strip down the tank every 6 months to clean beneath the plate...

UGF's certainly are not obsolete, and from a biological and mechanical standpoint, they are hard to beat. However, I'm a practical fish keeper, whom does not find stripping down a tank twice a year practical...

Externals are probably the next best thing however, and only needing maintenance every six months or so are a more practical option for filtration. Smaller tanks below about fifty gallons however can be filtered on internals though with satisfactory filtration results

All the best
Rabbut

 

[waterdrop]

I agree with all the others above on the criticisms. These are old technology. Nice info there from rabbut and aaron.

UGFs and reverse-UGFs fall into that category of equipment that can be made to work ok by an experienced aquarist who knows all the tricks and is very regular with the needed maintenance and diagnostics of the thing. But for beginners or those who don't figure out all the ins and outs of these filters, they can be quite a mess in my opinion. There have been a number of beginners with these in the time I've been a member here and nearly all of them have struggled with serious problems with their UGF.

~~waterdrop~~