Originally Posted by pepetj

As far as biological filtration, which in my opinion is the most critical, it is hard to beat. I read a couple of articles where experienced fishkeepers (Carl Strohmeyer from Americana Aquarium Products is one of them, don't recall the others) compared somewhat identical tank settings and the old sponge filter was not surpassed by advanced systems, such as bio wheel technologies.

For the article by Strohmeyer:
http://americanaquariumproducts.com/...iltration.html

I use sponge filters either as main/solo or back-up system. My 5.5gal Cherry Shrimp tank has two Hagen Elite fry sponge filters (with charcoal media removed) as only system. My 29gal Angelfish tank has a Hagen Elite dual sponge filter as back up (I inject CO2 there so it is ideal for minimal water agitation) as a ToM Rapids Mini-Canister filter acts as main unit.

Then in my Breeding Rainbowfish tank system I keep either a Hydro Sponge Filter-III or Hagen Elite dual sponge that are intended to stay as main tank when breeding occurs (to avoid the strong suction of power filters damaging fry and also to provide free baby food from the micro-algae and micro-fauna that grows around it).

I barely rinse gently in tank water once a year if needed. The organic film that look like sludge might look ugly but it usually allows enough water to pass through that its biological filtration capabilities stay a top but its mechanical filtration qualities decline. Tall plants or driftwood can cover them from sight.

I am a fan of Sponge filters. Easy technology that allows for battery operated airpumps keep a back up filtration running during power outages. I use two Hagen Elite dual sponge filters in a 20gal long in my office, where the emergency plant won't enter during weekends. (Black outs are a part of daily life events in Santo Domingo).

Pepetj
Santo Domingo