Confused with undergravel filters!

[fish_face]

I am sooooooo confused. I have never had an undergravel filter, always an inbuilt sponge canister one. I had had the tank about 9 months with no problems when I had an unexpected and major ammonia spike recently and lost loads of fish I thought that it was due to changing the tank around (and cleaning it at the same time), taking out all the small fish and adding quite a few new ones.

Anyway, a friend of mine said it was my gravel, even though I vac it and it always looks pretty clean. I've noticed that the vac does take out alot of mess when I do it.

He said that I should have an undergravel filter, even with all my catfish, what does everyone think?

 

[Morrgan]

I think UGFs are no longer a good option, there are better types of filtration to choose from nowadays. Reasons:

- The UGF needs a flat bed of sand to function properly and to make sure no anaerobic spots appear (the breeding ground of anaerobic bacteria, the ones that produce possibly poisonous compounds). If you keep digging fish, it just won't work like it's supposed to. You'd also need to do without large decorations, because they will make the water flow through the filter uneven.

- The UGF is bad for plants' roots. This may not be a problem for people who don't keep live plants, but I like my jungles.

- It just isn't effective enough compared to many of the other options today. If you want better filtration, get for example an outer canister filter (really something to consider for tanks from 200 l up).

I think your explanation for the ammonia problems is more likely than your friend's. If the bottom material is gravel and you vacuum regularly, there shouldn't be much of a problem. Well, unless you have an excessive layer 6 inches thick or something.

 

[Dubby]

I'll second the opinion that the ammonia was the problem and not the lack of UGF. If you are using only an internal canister filter for your 350L I feel the filtration maybe inadequate. Might consider looking at larger external filters such as the Eheim classic.

 

[Jen]

A while back I had the same problem. I was doing a cleaning, and after doing a gravel vac and still seeing a ton of junk come up after reaching my desired water removal, I wanted to get more of it out. I move all my plastic plants and stones from half the tank, and stirred up the gravel getting it all in the water so I could get it with my net. Worked marvelously, but the next day I had 5 deaths. I couldn't figure out why until I took a water sample to get tested. My ammonia was sky high, and he told me that I probably stired up a pocket of trapped ammonia that i was just missing with the gravel vac. It was probably under a plant or something.

I'm very sorry to hear about your loses though. It is from these happenings that we learn!

 

[LifeBear]

If your vac is picking up large amounts of yuck, then you are probably over feeding.

UGFs work ok BUT you have to keep them clean. If your regular gravel was dirty, a UGF will just make it WORSE.

I have always heard that sand was not good for a UGF, because it gets compressed too much for the water to flow through and creates anaerobic spots.
Large rocks and ornaments do the same.
It is bad for live plant roots, they get tangled in the grate. It is also bad for fry, if you should have any. They have trouble with getting sucked down.

There are better ways to filter, if fish waste is what you are vaccuuming up. If it is uneaten food, you might want to adjust how much you are feeding.

 

[eudielynn]

I have an UGF and although it does an okay job, it isn't great. I doubt very seriously that it would have solved your problem. I have a UGF because it came with the tank set up and I didn't know any better at the time. I'll be yanking mine out as soon as I have the time and energy to break down my big tank and pull everything out. Right now I'm running a small internal filter to help the UGF out. And they don't go with sand.

 

[Undawada]

UGF = bad.

Some people will disagree, but most won't.
They are alright for small tanks, but sponge is even better.

Notably, though, I do have one person in my fish club who uses UGFs in big cichlid tanks, but he combines them with other filters and powers them in reverse with a strong powerhead. It's a weird setup, but there you go.

 

[Jen]

Ohhh... putting the UGF on reverse... that'd be cool. It would help to move things around in your gravel, and give a kind of 'hot spring' effect. I would think it would help with better water circulation, without creating too much surface disruption for us with planted tanks.

 

[Tropjunky]

UGF is bad but it does offer almost unbeatable bio filtration but that fact isn't relevent cos most modern filters can offer enough bio filtration for a tank