Sponge filter questions

[aardvark1]

ordered and received one of these:

Lustar Hydro-Sponge Filter 1 (http://www.bigalsonline.com/BigAlsUS/ctl3684/cp19170/si1379356/cl0/lustarhydrospongefilter1)

Going to cycle it in one of my bigger tanks to use to set-up my 10 gallon as a QT/hospital tank when needed.

Reading on the box, they come in various sizes good for up to a 150 gallon tank.

Got me to thinking-there has to be a catch! So cheap, do they filter as good as a HOB type filter? WHy spend $100 (and up) for a canister filter for a large tank when for $9.99 for one of the biggest sized ones and say, $10 for an air pump to do the same thing.

Only drawback I can see is the size; the 10 gallon one I got is rather large...

Or am I missing something in the "Big Picture"

:look:

[Star_Rider]

actually they don't really filter out particulate matter that well.

they are in essence a bio-filter..heavy particle will settle near the base of the sponge and on the sponge..you will need to do almost daily maint on these.

they work best in a bare bottom tank.

I use mine in a hospital/growout tank. I use a hob in conjuntion with the sponge to help filter heavy particles.

the sponge is great when rearing fry..low circulation(sponge filters draw water from all around the sponge so the current is diffused.

[Rbishop]

They are great for fry tanks and to collect bacteria to establish a new tank or get a qt tank up and operating when needed.

[Rallysman]

They are great for added biological filtration too.
I like keeping them in my tanks with other filtration. (Plus, it never hurts to have an established filter laying around:)

[dorkfish]

The catch, aside from what has already been mentioned, is that they can be considered ugly and eventually the sound of an air pump gets annoying.