Why are bottom filters poo pooed?

[MannyE]

When I first started keeping freshwater fish, I set up a small 30 gallon with an undergravel filter and a small powerhead. After a month or so to cycle the whole thing, I put some "test fish" (a few guppies) and they did great.

I used RO water, added minerals from one of those African Ciclid lakes (all my fish seemed to love that stuff..like an 1/8 of a teaspoon at water change time) and had a very happy community tank. Twice a year I would vacuum and 10% water changes every whenever (not to disciplined about that).

The filter was invisible, the tank looked great, the fish were happy and long lived... why then does every "professional" I talk to tell me they are crap?

What they don't tell me is why, and what makes an ugly box hanging off the back better? (there's the question after all the preamble)

I ask this because I am about to get my first monster and I'm going with the big tank right away instead of working my way up from 20 to 50 etc. Probably 150 gal and some oscars and plecos.

I should stress that it's important to me that my tank look pleasing to the eye and as much as possible (given the gravel real estate that must remain clear) be decorated and planted, but I am aware that even 40% coverage of the bottom reduces the effectiveness of the filter (and fish count) dramatically.

Again the question... why NOT a bottom filter instead of a rear mount or external wet/dry thingamabob?

Hows that for a first thread? I figure after all this lurking I'd start with a bang.

 

[hillbilly]

Simple answer. The huge amount of waste produced by large fish would quickly turn the tank into a cesspool without more effective filtration, more water changes, and gravel vacs.

 

[Gonzaga]

Undergravels are not as good for CA/SA cichlids because they are known diggers. They will constantly dig down to the bare filter and it will become clogged very easily. If you're going to buy a big tank I'd suggest getting something with a built in overflow, either in the corners or in the middle. Much better filtration and an overall cleaner look.

 

[Bderick67]

yes, the hang on back filters are very ugly and look horrible...but they are on the back of the tank, which you don't even look at. As far as the lift tubes and powerheads, talk about a sore sight, you always had to aquascape to hide the crap. The inside of the tank you are always lookig at.

Ug filters can work fine and require regular gravel cleanings to preform properly.
The drawbacks are;
-very poor mechanical filtration(they can't remove the particle waste from the aquarium)
-can not handle larger bioloads(caused by heavily populated tanks or larger fish)
-certain fish (cichlids)dig up and expose the filter plates which creats a bypass(the gravel is your filter media)
-can not be used with sand or in bare bottom tanks.
-not good for planted tanks(which require reduced gravel cleaning)

I'm sure there are other drawbacks too, which others will add.

 

[ethnics]

the reason ur tank worked out, was because your fish were the size of my pinky and generated poo the size of my nose hair.. monsters produce poo the size of a paperclip or whatever u wanna compare it to. with only an ugf, wheres all that poo gonna reside? under the rocks, stuck in that ugf, fouling out ur whole tank... even when u gravel vac, you can't get the crap stuck in that ugf so water changes are almost useless cuz the new water fouls out quicker then it went in. power heads do not generate any bio filtration unless it has the sponge thing attatchment on it, but still will not get the job done once u step it up to a monster tank. you need heavy filtration which u will not get from ugf and only a power head.

 

[ewurm]

Why not use a horse and buggy instead of driving to work? The new filters make lif easier.

 

[Oddball]

I used Dr Stephen Spotte's method when I used UG filters on my 180 and 240 poly tanks.
Place a layer of coarse pond poly pre-filter material or bonded pad between the UG plate and substrate. The material provides 800 times more surface area for bacteria to adhere to. The additional bio-filter
-aids in rapidly breaking down wastes.
-prevents the UG plate slots from getting clogged.
-Keeps sludge from collecting below the plates.
-provides excellent anchoring points for plant roots.

The 240 ran for over 2 years with 17 polys and 2 asian aros. There was also an over-size W/D filter running roughly 1600gph at the head. Routine gravel washes/water changes kept the big stuff at a minimum in the pads.
When I had to break the tank down to move, the bonded pad was still white on 1 side and there wasn't any sludge below the plates. Just a little bit of dust flakes/grit.