Lifting power for sponge filters: Big bubbles vs. small bubbles?

[Prince]

Stole this from MFK

Will an open airline blowing huge bubbles is going to generate a lot more movement than an army of tiny bubbles. But the army of tiny bubbles will provide a more consistent pull instead of a pulsing one, right? Does anyone know the pros and cons of airstone vs. open line in a sponge filter?

 

[iamzrad]

I'd say consistency is with smaller bubbles.

 

[Cartel]

I use an air stone in my sponges it just looks more efficient to me when I look at the roil it makes.

 

[dogofwar]

I don't use airstones.

Airstones clog and I can run more sponges/boxes without stones than with...so I don't use them. Without airstones makes more bubbling noise than with, though.

In most of my tanks, I couple a box filter with a sponge filter. I tend to use LESS air through sponges to minimize their ability to serve as mechanical filters...and more through the boxes (so that they serve as the prime mechanical filter). Boxes are easy to clean, while sponges are a PITA...

Matt

 

[Frank Cowherd]

If you compare large bubbles and small bubbles using the same total amount of air, the smaller bubbles will actually move more water.

And there are a couple other factors. The longer the time that the bubble is in the filter housing or tube, the more air it moves, so if you can lower the point at which the air is released from the end of the airline into the water column, the more water it should move. Most box filters and sponge filters are already designed to put the air into the water column at its lowest point. However, Hydrosponges give you the option of adding another extension to the air line inside of the filter and the option of having a plastic tube extend above the filter, the longer both extensions are the more water will be moved by the air.

The other factor is the distribution of the air where or as it enters the water column. You can actually buy a device that sits on the top of a hydrosponge which is connected to the air line. It distributes the air by releasing it in a circle around the circumference of the water column coming out of the sponge filter. It works but I find it requires a lot more air than am willing to use on any one filter. A similar design was available at the recent PVAS convention and sold by Stephan Tanner with the tank dividing sponge filters. That device was connected to an air line and provided a blanket of air around the lift tube for the water. With a circle of holes in the lift tube, the water column was moved by a circular column of small bubbles. Comparison of the amount of water moved by the circular column of small bubbles and a single stream of bubbles from the same air line, showed a much higher flow from the circular column of bubbles.

 

[RIFT_LAKES_RULE]

I'm with Matt, I don't use airstones because they clog. Definitely noisier but I'm cool with it.

 

[davidhusker]

i hate sponges without airstones, but is has nothing to do with effectiveness. I just like the quietness and the extra bubbles

 

[Tony]

I don't use airstones.

Airstones clog and I can run more sponges/boxes without stones than with...so I don't use them. Without airstones makes more bubbling noise than with, though.

I'm with Matt, I don't use airstones because they clog. Definitely noisier but I'm cool with it.

Me three.

 

[Charlutz]

I'm not sure you get enough of a benefit with an airstone v. without in terms of water movement to make that a critical factor in your decision. If you're not getting enough water movement, get a bigger pump. I also read somewhere that it's the reverse pressure of having the air in the tube that sucks the water through the sponge and not the actual "lift" of water by the air, but still, it doesn't matter for me. I use airstones because a half dozen bubbling filters are too loud for me, let alone a dozen or two.

 

[Sonny Disposition]

One other consideration--you'll probably get more dissolved O2 into the water with an airstone than you will without. The smaller something is, the more surface area it has in relation to its size. So lots of small bubbles have more surface area than a few large ones. More surface area means more gas exchange--more 02 entering the water, more C02 leaving the water. And it's not just the fish that need 02--it's also the detnitrifying bacteria that break down ammonia.

 

[dogofwar]

Running a lot of air through sponges turns them into poop-sponges (mechanical filters) rather than nitrifying bacteria colonies (bio filters).

I run my sponges relatively slow (so they don't get dirty as fast) and the (easy-to-clean) boxes with lots of air...

Matt

 

[fischfan13]

One other consideration--you'll probably get more dissolved O2 into the water with an airstone than you will without. The smaller something is, the more surface area it has in relation to its size. So lots of small bubbles have more surface area than a few large ones. More surface area means more gas exchange--more 02 entering the water, more C02 leaving the water. And it's not just the fish that need 02--it's also the detnitrifying bacteria that break down ammonia.

Great point Bob!
Airstones, IMO, run sponge filters much more efficiently and, of course, quieter.

 

[Dragonkeeper]

I don't use airstones, they just clog to easily. Also an interesting idea from dogofwar. Although i find that the sponges are easier to clean then the box filters. A few squeezes under a high pressure hose and they are fairly clean. Plus i believe that most of our beneficial bacteria is in the gravel surface and any rocks or other adornments we use. Just in case i clean one sponge every 6 months so one is always fully cycled.

 

[UNCLERUCKUS]

I don't use airstones, they just clog to easily. Also an interesting idea from dogofwar. Although i find that the sponges are easier to clean then the box filters. A few squeezes under a high pressure hose and they are fairly clean. Plus i believe that most of our beneficial bacteria is in the gravel surface and any rocks or other adornments we use. Just in case i clean one sponge every 6 months so one is always fully cycled.

+1

 

[dogofwar]

I'm (oddly) fanatical about the cleanliness of my box filters.

I try to switch out the fluff at least every two weeks. Weekly water changes, use of just a bit of gravel/sand (so that it's easy to siphon out crud) and frequent mechanical filter-changing is a good way to keep nitrates low...

Matt

 

[UNCLERUCKUS]

I'm (oddly) fanatical about the cleanliness of my box filters.

I try to switch out the fluff at least every two weeks. Weekly water changes, use of just a bit of gravel/sand (so that it's easy to siphon out crud) and frequent mechanical filter-changing is a good way to keep nitrates low...

Matt

+1

 

[SubMariner]

If you compare large bubbles and small bubbles using the same total amount of air, the smaller bubbles will actually move more water.

And there are a couple other factors. The longer the time that the bubble is in the filter housing or tube, the more air it moves, so if you can lower the point at which the air is released from the end of the airline into the water column, the more water it should move. Most box filters and sponge filters are already designed to put the air into the water column at its lowest point. However, Hydrosponges give you the option of adding another extension to the air line inside of the filter and the option of having a plastic tube extend above the filter, the longer both extensions are the more water will be moved by the air.

The other factor is the distribution of the air where or as it enters the water column. You can actually buy a device that sits on the top of a hydrosponge which is connected to the air line. It distributes the air by releasing it in a circle around the circumference of the water column coming out of the sponge filter. It works but I find it requires a lot more air than am willing to use on any one filter. A similar design was available at the recent PVAS convention and sold by Stephan Tanner with the tank dividing sponge filters. That device was connected to an air line and provided a blanket of air around the lift tube for the water. With a circle of holes in the lift tube, the water column was moved by a circular column of small bubbles. Comparison of the amount of water moved by the circular column of small bubbles and a single stream of bubbles from the same air line, showed a much higher flow from the circular column of bubbles.

One other consideration--you'll probably get more dissolved O2 into the water with an airstone than you will without. The smaller something is, the more surface area it has in relation to its size. So lots of small bubbles have more surface area than a few large ones. More surface area means more gas exchange--more 02 entering the water, more C02 leaving the water. And it's not just the fish that need 02--it's also the detnitrifying bacteria that break down ammonia.

Who needs the Mad Scientist (Paul Mclasky) when you have both of these gentlemen, who happen to be members of the CCA.

Great information my friends, Thank you very much.

 

[Avatar]

"Poop' filters? Come on now...

...a 'mechanical' foam filter does not stop being a biological filter just because it's amalgamating particulates, which from a microbial POV are very likely just as useful for colonizing as the sponge itself and in some measure (e.g., detritivores - what's a sh*t eating microbe called by the way?) the 'main event'. Thus do I imagine. Granted if the foam gets so clogged there's little or no water passing through it pretty much stops being biological as well as mechanical which is why I use 40 gallon sponges (imagine a 16 oz. can) in 10/20 gallon tanks - less frequent need for squeezing them clean in old water during water changes which has never struck me as too or any more tedious/time-consuming than rinsing out box filters.

My favorite ap for sponges is to mount little power-heads on stubby uplift tubes. Have to service then more often because they clog up faster but you never/rarely have to siphon the tank and they create steady but gentle circular water movement that brings the sediments to the filter. And with a breather tube attached you can even inject air bubbles into the flow to increase dissolved oxygen/CO2.

Last: would love to get over the notion that sediments are bad or unattractive. If the biological aspects of filtration are sufficiently robust the sediments should be thoroughly 'digested' and therefore for all intents and purposes inert. Chris Stroud up in PA has thriving tanks that are crystal clear even though there's tons of silt in them, but as it's all broken down it doesn't pose a problem to the fish (unless perhaps you're doing Africans and it drags the pH down but even that reaction should eventually exhaust itself, neh?).

One of these days I'm going to have to build a vast cascading series of front-glassed aquatic habitats that sequentially flow into one another with a single kick-a** SOA filtration system at one end so I can deal with one filter set-up instead of dozens. Or maybe a huge circular arrangement with a central cascade system that flows into a bunch of separate but abutting habitats simultaneously. Just as soon as I get past all this 'got to save the planet' nonsense. Right....

 

[dogofwar]

Definitely not arguing that a sponge will cease being a bio filter if it's also serving as a mechnical filter...

My point is that I'd rather have sponges work MORE as bio filters and LESS as mechnical ones (by limiting the amount of flow through them)...and let the boxes serve as the primary mechanical filter for the tank.

With a lot of flow, a sponge filter will do a great job of aggregating all of the poop, uneaten food, gunk, etc. from a tank. I just find boxes easier to clean than sponges.

With as many tanks (and as little free time) as I have, I try to make it as easy as possible to keep them clean and keep nitrates as low as possible. My strategy - which I agree isn't the only one - is to do weekly water changes...and to make removal of gunk as easy as possible (little gravel and frequent changing of box filters)...Hot water supply willing, I can clean all of the (~50) tanks in my fishroom in about 2 - 2.5 hrs...although I need to get the auto-water changing system re-set up...

Matt

Matt

...a 'mechanical' foam filter does not stop being a biological filter just because it's amalgamating particulates, which from a microbial POV are very likely just as useful for colonizing as the sponge itself and in some measure (e.g., detritivores - what's a sh*t eating microbe called by the way?) the 'main event'. Thus do I imagine. Granted if the foam gets so clogged there's little or no water passing through it pretty much stops being biological as well as mechanical which is why I use 40 gallon sponges (imagine a 16 oz. can) in 10/20 gallon tanks - less frequent need for squeezing them clean in old water during water changes which has never struck me as too or any more tedious/time-consuming than rinsing out box filters.

My favorite ap for sponges is to mount little power-heads on stubby uplift tubes. Have to service then more often because they clog up faster but you never/rarely have to siphon the tank and they create steady but gentle circular water movement that brings the sediments to the filter. And with a breather tube attached you can even inject air bubbles into the flow to increase dissolved oxygen/CO2.

Last: would love to get over the notion that sediments are bad or unattractive. If the biological aspects of filtration are sufficiently robust the sediments should be thoroughly 'digested' and therefore for all intents and purposes inert. Chris Stroud up in PA has thriving tanks that are crystal clear even though there's tons of silt in them, but as it's all broken down it doesn't pose a problem to the fish (unless perhaps you're doing Africans and it drags the pH down but even that reaction should eventually exhaust itself, neh?).

One of these days I'm going to have to build a vast cascading series of front-glassed aquatic habitats that sequentially flow into one another with a single kick-a** SOA filtration system at one end so I can deal with one filter set-up instead of dozens. Or maybe a huge circular arrangement with a central cascade system that flows into a bunch of separate but abutting habitats simultaneously. Just as soon as I get past all this 'got to save the planet' nonsense. Right....

 

[Avatar]

50 tanks in 3 hours? That's very almost disgustingly impressive.

Hard to argue with empirical evidence - tis a far better testimony than any other. You've clearly a much better efficiency than I can claim or attain what with ferrying 5 gallon buckets of water back and forth throughout my apartment.

One day I too will have a fish room...thus do I imagine.