The Woefully Underappreciated Sponge Filter

jcarson

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I'm seeding (6), 125g rated sponge filters for a big move (all my tanks to a temporary home while I build a new house). I put them in a trash can with 45g of tank water from a cycled 210g. Have them up & running and just squeezed out a nice cycled sponge filter in the can with the new ones. Anyone have a thought on how to "feed" ammonia for the next 3-4wks to get them cycles 100%? I was thinking like a fishless cycle with pure ammonia? Or a handful of feeders but don't want to risk any disease.
I saw on youtube where this guy drops a few raw pieces of shrimp in the tanks he has running without fish to keep his filters cycle.
 

Zimbick

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Jan 15, 2018
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I thought of that but was worried my fish room might smell like rotting fish...lol. but, that may have been easier than my ammonia experiment. 45g trash can, I thought (wrongly) that a 1/2cup of ammonia would get me to 4ppm. Trying to be smart (failed) I only added an 1/8 cup. Tested water didnt wait long enough for color to form b4 I added another 1/8 cup. Retested and had well over 8ppm water. Dumped it all. and started over, finally got it right with about an 1/8 of a cup. At least there weren't any fish sacrificed in my experiment.
 

Ulu

Redtail Catfish
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I have never run sponge filters until last year. Always undergravel with powerheads.
Now I run them in 8 of my 9 tanks, or in the sumps of the larger tanks.
I like the small air requirement and big bio-capacity.
Most tanks have another filter, HOB, or hybrid system.
But some run on sponges alone.
 
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jcarson

Plecostomus
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Does anyone know the difference in performance when it comes to dense vs. porous sponges.
I recently added a power head to a dense sponge and while the mechanical filtration has seemed to increase I noticed the sponge getting choked out with detritus and have to service it more than before.

I was wondering which has the higher capacity for bio filtration.
 

skjl47

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Does anyone know the difference in performance when it comes to dense vs. porous sponges.
I recently added a power head to a dense sponge and while the mechanical filtration has seemed to increase I noticed the sponge getting choked out with detritus and have to service it more than before.

I was wondering which has the higher capacity for bio filtration.
hello; I do not have an answer I can support or back up in any way other than make a guess. The often claimed notion is the beneficial bacteria (bb) we all look for need solid surfaces to colonize. Many look for very porous surfaces which makes sense. Using that criteria and given an assumption the more dense sponge has a greater surface area then it ought to hold the greater population of bb.
Using logic it ought to win but logic sometimes has a way of not translating into the real world.
A possible flaw is the denser material should flow water much more slowly so the bb deep inside have less opportunity to have ammonia/nitrite move by. Another possible shortcoming might be the smaller pores will become clogged up with junk further reducing effectiveness.

Many years ago ( well lets say decades) I used glass marbles as bio-media. The spheres packed well and still had plenty of gaps where water flowed. The marbles were easy to clean when loaded with detritus. I currently am curious as to how well the modern stuff cleans. Another assumption is the preferred method of cleaning. Sloshing the media in old tank water makes sense in that it preserves the bb. This method seems also to be too gentle to clean out the pores to much of a degree. Still wind up with most of the outside surfaces cleared so at least even with the glass marbles and maybe better. I tend to think glass marbles as bio media can be improved by getting smaller diameter spheres but not too small.

Back to the question. The more porous sponge will be my pick most of the time. I figure it will flow water some better at first and might even keep up with neutralizing ammonia/nitrite. It should also do some better as mechanical media and also be some easier to clean effectively with simple squeezes in old water. As I said lots of guesswork all based on just thinking.
 

Ulu

Redtail Catfish
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My feeling is that you don't want to flow the water too quickly through the sponge unless you're using it as a pre-filter primarily.

For best biologic action I believe you want flow to be very slow.

I put mine in the sump because it makes them easy to clean right there and the aquarium looks better without them.

For cleaning I take out the floss and discard, then I rinse off all of my bio media and sponge filters right in the sumpwater.

I pump out the bottom sump water for my garden and rinse it all with some more tank water and pump it out again before I refill the system.

I generally don't siphon my aquariums very often now, because almost everything is going down into the sump.
 

flukeone

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I've been thinking...

I have a 66g tank running on a canister. I was thinking about replacing the airstone in the tank with a sponge filter. It doesn''t cost much, uses the already existing air line and will still provide surface agitation to oxygenate the tank.

what do you think? makes sense to run both a canister and a foam filter? will it provide enough surface agitation?
 
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islandguy11

Redtail Catfish
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Sep 17, 2017
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I've been thinking...

I have a 66g tank running on a canister. I was thinking about replacing the airstone in the tank with a sponge filter. It doesn''t cost much, uses the already existing air line and will still provide surface agitation to oxygenate the tank.

what do you think? makes sense to run both a canister and a foam filter? will it provide enough surface agitation?
I would highly recommend to do you like you're asking; with a sponge filter (have 'em on just about all my tanks) -- you'll usually get less bubble action/flow compared to an airstone, but in case your canister filter ever has a problem you'll have at least some bio filtration going on. Likewise if the electricity goes out you can easily hook up a battery powered air pump to your sponge filter, it could help to save your fish.

Denser sponge foams (slower flow) are better for bio filtration, but they'll also clog up faster than medium or coarser filters, which are better for mechanical filtration. I personally prefer kind of medium porosity, like the bigger ones made by Ocean Free.
 
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