Undergravel Filters Yes Or No?

[Adolf88]

I've always went with these and really like how they work and the look of the tubes in the corners filtering your tank.

As long as you had an external filter running as well will I have any problems to run an UGF in a 6" tank?

Does anyone else still use these?

 

[nurglespuss]

UGF in a 6" tank?

Does anyone else still use these?

In a 6 inch tank? ;p lol

I used to always use these, but as time moved on, and equipment got more reliable and cheaper too, I switched to externals. The maintainance is easier, plus if you wont to use sand, UG really isn't an option.

There are some (though unproven) suggestions that UG filters are detrimental to 'bottom dwelling' foraging fish (like catfish), however in a well maintained system, I've never had that problem when I used them.

If your going to combine them with a power filter, and like the bubbles, you may be better off using an external, and an airpump with a bubble wall etc.?

 

[shelaghfishface]

nooooo!!! they collect the rubbish that should be going OUT of the tank.. disgusting inventions!!

 

[snake007]

nooooo!!! they collect the rubbish that should be going OUT of the tank.. disgusting inventions!!

+1

Horrible inventions!
Dont even bother with it, for your tank size maybe a couple tetratec ex2400

 

[XeroTolerance]

Not get one of them. They sound like they help but they really are more pain than their worth.

 

[MBOU]

They are defunct for a reason!

 

[shelaghfishface]

get a sexy FX5! even second hand theyr fab
the 2400 have been known to be a little noisey

 

[jme369]

Surely a UG filter ends up just using the gravel as a mechanical filter, meaning that the detritus stays in your tank polluting?

 

[nurglespuss]

Surely a UG filter ends up just using the gravel as a mechanical filter, meaning that the detritus stays in your tank polluting?

Yup, they need constant maintainance to remain effective, light feeding, regular surface vac of gravel (being careful not to disturb bed too deeply), regular changing/cleaning of air diffusers etc. Hard work really.

 

[BLUFOX]

imo Under gravel filters work ok for biological filtration, but they are horrible for mechanical filtration - they trap waste in the gravel and under the filter place and can lead to gradual decline in conditions. I dont' recommend them

 

[nmonks]

Okay, some comments here I fear from people who haven't used them!

Undergravels can and do work extremely well, provided you know their limitations. They can offer extremely good levels of biological filtration. The silt that can collect in the traditional undergravel filter can actually work like an extra layer of biological media. The bacteria love the stuff! So provided you clean the thing periodically (once or twice a year) then it works fine. You shouldn't use a traditional undergravel filter for big, messy fish -- there'd be so much silt collecting too quickly to be cleaned away with an annual check-up. But for very small fish like neons, an undergravel can work well.

On the other hand, a reverse-flow undergravel is one of THE BEST filters possible for big, messy fish. Why? Because only clean water is pushed into the undergravel, and that water is pushed from underneath upwards, forcing silt into the water column where it can be sucked up easily by the canister filter. So you have the easy-to-clean external canister removing solid waste while the reverse-flow undergravel provides biological filtration. This is an excellent combination when designed and set-up properly.

The main limitations are these:

Firstly, undergravels are essentially incompatible with plants. Epiphytic and floating plants would be okay, but anything with roots is likely to do poorly. Even if such plants did thrive, chances are their roots would get in the way of water flow, reducing water flow through some parts of the gravel bed while increasing flow elsewhere. That's bad, and an undergravel with a "short circuited" flow of water isn't going to filter water adequately.

Secondly, undergravels dramatically limit your options in terms of aquascaping. Apart from a few rocks or roots, you need to keep most (80% or more) of the gravel bed clear and perfectly flat. Terracing, large caves, heaps of rocks, big bogwood roots and the like are all out of the equation.

So the ideal situations would be tanks such as small community tanks with plastic plants and a couple of ceramic ornaments, or else large tanks with big, open water fish such as South American cichlids or goldfish that don't care about decor much. The former example would be served well by a plain vanilla undergravel, and the latter with a reverse-flow system.

For situations where you want lots of decor, plants, live rock, etc., undergravels aren't good choices. These are the most popular ways to decorate tanks nowadays, and that's why you don't see undergravel filters very often. But in and of themselves, undergravel filters are not obsolete, and as I say, in some situations they could be good value, reliable filters to choose.

Cheers, Neale

 

[AbbeysDad]

When I got back into the hobby, I was surprised at the long standing controversy over the lowly under gravel filter. The UGF is one of, if not the oldest biological filter and it works great 30+ years later. It's only down fall is that it is often not managed well and can cause disaster. Name a filter that you can just run and run and never service? There isn't one! But somehow, people often just run the UGF without servicing the filter media (gravel). If the gravel is routinely vacuumed, the UGF performs very well.

On the other hand, with the possible exception of the cartridge HOB filter, today's power filters and available bio-medias make the UGF somewhat obsolete.

 

[snazy]

I have one in my fry tank and to be honest I find it very good for that purpose. Can't have it any easier without having to worry about filter media, sucked up fry by the intake tube, etc..I don't have to switch it off at water changes and the few times I decided to clean the motor head there was nothing to clean.
I try to siphon also through the filter plate openings by moving the gravel away and barely something major comes up and is certainly not more than the junk in my other tank that has 2 normal filters in.

 

[Adolf88]

I see quite a few people can't stand them judging by the comments so far.

Just I've always used UGF's and never had any problem with them and was thinking of running a UGF and 1 external filter in a 6ft tank (due to a reply on the other topic I've decided it's the right size since it won't be my perm home and this is easier to work with) and was just wondering if it's still okay to use it in this size tank, I don't personally like internal filters or the look of them and really wouldn't want to use them as I like the old classic way UGF.

Plants I'd like only a few rooted the rest floating wouldn't bother me and perhaps maybe 1 or 2 bog wood pieces and one ornament.

 

[nmonks]

A high performance canister linked to a 8-10 cm deep medium grain gravel bed would work well together, forming a reverse-flow undergravel filter. Eheim, for example, sell kits of converting their canisters into reverse-flow undergravels.

You have to keep the substrate more or less the same depth throughout, so if the fish do a lot of digging, then the undergravel filter won't work so well. A gravel tidy could be used to prevent this sort of problem; i.e., go to the garden centre, get some sturdy green pond mesh cut to size, and put that on top of most of the gravel, topping it with about 2-3 cm of gravel leftover to hold it in place. A few carefully positioned rocks or roots would add extra security.

Cheers, Neale