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Should I switch to a sponge filter?

13K views 29 replies 8 participants last post by  Byron 
#1 ·
Hey.

Got a new question. I've been reading up on sponge filters a lot.. that they're beneficial in planted tanks because they help keep CO2 in the tank. I don't have or really think I am going to add CO2 system to my tank, so I'm sure it's important to keep the CO2 that's in there available for the plants.

For those who haven't seen my other posts of me asking a million questions :-D (which I thank you all for your help, a million times over!) I currently have a 28 gallon tank with some plants, with plans to add a few more / a lot more. Currently, there's crypt wendtii (maybe just one.. two disappeared but I'm hoping they'll come back), another crypt (think it's a crypt at least) which looks like a grass looking plant, quite a few small (but growing) amazon swords in the back, some of what I'm pretty sure is Red Ludwigia, marimo balls, some floating wisteria, and a one of the plants that come in a tube at petco which they labelled as something like Compacta. I know everyone talks poorly of the petco/petsmart tube plants - but that's where I got my swords and wisteria and so far they're doing fine, as is the Compacta, though I've been keeping and eye to make sure that one doesn't fail.

My only concern with a sponge filter is noise.. I've heard they're terribly noisy. The filter I have right now is an Aqueon Quietflow 30 and it's wonderfully quiet. I only hear the noise of a small waterfall where the water's pouring out into the tank; the filter itself is silent and I love that. But the flow is fairly strong so I haven't planted anything under it for fear the plants won't survive. I've got a fake "bonsai" tree under it to try to slow down the impact of the water flowing in. If I get a sponge filter, how loud are they? I had a bubbler in my tank previously (before adding the plants) and it was a tolerable noise, but any more bubbling than that and I think it would get annoying. The tank is currently in my living room, so I don't want it to be too loud.

If a sponge filter would be too loud for me, should I try the plastic bottle "mod" I've seen, where you tape the cut soda bottle over the outflow to disperse the flow a bit more. Or, I've also seen a mod where people have installed a sponge on the outflow of my filter which also inhibits the water flow a bit, while at the same time offering another surface area for bacterial growth.

Also, should I move my heater to the center of my tank for more even heating? Right now I've got it on the opposite side of my filter, and away from any plants. If I put it in the middle it would be behind the big "grassy" crypt - will the plant be ok with the heater there?

Any opinions? If it matters, my stock currently is 1 angelfish, 5 harlequin rasboras, and 7 very young danio (no bigger than the rasboras, some a bit smaller). I'm planning to rehome the danio and add some more rasboras and some corys. I have a sand substrate.. some sort of fluval heater and I've already mentioned my filter. My tank is about 2 months old, and the decorations were all transferred from another tank. I haven't checked my parameters since about 1-2 days ago but my ammonia and nitrite were at zero with the nitrite at like 20ppm or somewhere around there. I can do another test if you'd like.

Last question is -- if I am to switch to a sponge filter, I know I wouldn't want to turn off my current filter because of the bacteria colony in it. Would I need to run both filters to help with growth on the new filter or would some grow with it just being in the tank. I've been looking inside the HOB filter and I just don't know if I can stuff any sponges inside it.. Should I take something out (like maybe the filter cartridge?) and replace with the sponges. I even have a small filter cartridge for another brand that I might be able to throw in with sponges - so I'll still have the chemical filtration as well.

I'm a newbie to this.. sorry. Trying to learn as much as I can! I was originally going to go with a sponge filter, but heard the were noisy so I got the HOB instead. Now I'm doing my research about planted tanks (after already having planted) and seeing that I may have made a mistake.
 
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#2 · (Edited)
I've been reading up on sponge filters a lot.. that they're beneficial in planted tanks because they help keep CO2 in the tank. I don't have or really think I am going to add CO2 system to my tank, so I'm sure it's important to keep the CO2 that's in there available for the plants.
Umm, where did you hear that? Sponge filters don't keep CO2 in a tank any better than any other filter. The less surface agitation, the better from a planted tank standpoint. Could you be more specific?

My only concern with a sponge filter is noise.. I've heard they're terribly noisy. The filter I have right now is an Aqueon Quietflow 30 and it's wonderfully quiet. ..... I had a bubbler in my tank previously (before adding the plants) and it was a tolerable noise, but any more bubbling than that and I think it would get annoying. The tank is currently in my living room, so I don't want it to be too loud.
If you use an air-pump driven sponge filter (with an airstone), you'll hear the pump much more than the bubbles, usually. A powerhead would likely be quieter, especially if the discharge is under the water surface.


If a sponge filter would be too loud for me, should I try the plastic bottle "mod" I've seen, where you tape the cut soda bottle over the outflow to disperse the flow a bit more. Or, I've also seen a mod where people have installed a sponge on the outflow of my filter which also inhibits the water flow a bit, while at the same time offering another surface area for bacterial growth.
Personally, I'd just purchase a small Eheim canister filter before going to all that trouble :)
I think you mean they add the sponge to the HOB intake? That works well.

Also, should I move my heater to the center of my tank for more even heating? Right now I've got it on the opposite side of my filter, and away from any plants. If I put it in the middle it would be behind the big "grassy" crypt - will the plant be ok with the heater there?
If my heater is in a water current, my tanks heats a little more evenly, but it's no big issue either way. The only problem I have with my plants is one particular sword has a leaf that turns yellow exactly at the point where it touches the heater in my 55 gallon. Plant will be fine, but I'd give a little space (a fraction of an inch or more) from the heater.

Any opinions? If it matters, my stock currently is 1 angelfish, 5 harlequin rasboras, and 7 very young danio (no bigger than the rasboras, some a bit smaller). I'm planning to rehome the danio and add some more rasboras and some corys. I have a sand substrate.. some sort of fluval heater and I've already mentioned my filter.
I'm sure someone has mentioned that angels need to be in a group and if you add two additional angels, you'll need a bigger tank to house them at their adult size!

if I am to switch to a sponge filter, I know I wouldn't want to turn off my current filter because of the bacteria colony in it. Would I need to run both filters to help with growth on the new filter or would some grow with it just being in the tank.
Just run the sponge filter, along with the current HOB for a few weeks to establish the bacteria in it and that should do it. HOB's are the noisiest type of filter, in my experience, BUT you can have a planted tank with an HOB without a problem.
 
#3 ·
Umm, where did you hear that? Sponge filters don't keep CO2 in a tank any better than any other filter. The less surface agitation, the better from a planted tank standpoint. Could you be more specific?
Yes, I meant the less surface agitation. Sorry, I wasn't sure how to word it appropriately! I know it doesn't add to the CO2, but that type of filtration can limit the loss of CO2 - is that correct? :) Sorry. Either way, I know as far as CO2 for plants sponge filter > HOB.

If you use an air-pump driven sponge filter (with an airstone), you'll hear the pump much more than the bubbles, usually. A powerhead would likely be quieter, especially if the discharge is under the water surface.
I have two air pumps now, one is weaker than the other. The bigger one is a tetra whisper air pump and it's relatively quiet. I can hear it, but I was using it for my bubbler and the noise of the air pump didn't bother me. I can place it on carpeting so it can be very quiet. The only problem is I'm not sure how big of an air filter I would need for a sponge filter. I bought it so long ago I don't remember, but I'm going to assume it was for a a 20 gallon tank because that's what I had before this tank. Would that be sufficient? Or too much? Or is a powerhead really a better option? I figured if I already had an air pump lying around unused, I might as well use it instead of the powerhead.


Personally, I'd just purchase a small Eheim canister filter before going to all that trouble :)
I think you mean they add the sponge to the HOB intake? That works well.
I'd buy a canister filter if I had the money, but I just don't have that sort of money to spend on a fish tank at this point.


If my heater is in a water current, my tanks heats a little more evenly, but it's no big issue either way. The only problem I have with my plants is one particular sword has a leaf that turns yellow exactly at the point where it touches the heater in my 55 gallon. Plant will be fine, but I'd give a little space (a fraction of an inch or more) from the heater.
Thanks! I guess I will consider moving it. I don't really want to move the plant in the center because it's a crypt.. but I can always move the filter a little closer to the center. I guess is it beneficial to have it near the filter then to increase it's exposure to the currents?


I'm sure someone has mentioned that angels need to be in a group and if you add two additional angels, you'll need a bigger tank to house them at their adult size!
I am aware of that - it was a donated angel that I'm still considering if I want to donate it or not. I don't have room or plans to get a bigger tank for the room for more angels, because I would absolutely need more than 3 -- the recommendation is a breeding pair or 5+. I could keep a breeding pair, but not with anything else so this isn't really something I'd like to do.

Just run the sponge filter, along with the current HOB for a few weeks to establish the bacteria in it and that should do it. HOB's are the noisiest type of filter, in my experience, BUT you can have a planted tank with an HOB without a problem.
I know a lot of HOB can be loud, but the one I have doesn't bother me. I don't hear the filter itself, just the water outflow which is fine by me.
 
#4 ·
I'll just pick up on your subsequent questions.

A sponge filter will be more than adequate for a 28g tank with the mentioned fish, all of which prefer less water movement; the issue with the HOB is not so much plants as fish. I have a dual sponge in my 29g, the Elite made by Hagen [photo attached below]. A small air pump will be sufficient for one sponge filter, so you're all set on that.

The heater is best positioned close to the filter return so the current (and even with a sponge there is a slight current) moves the heated water into the tank.

Byron.
 

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#5 ·
Ok, good to know. The fish have seemed ok with the current thus far (the danio sometimes play in it, but they're not staying anyways) but I know the rasboras generally avoid that corner of the tank (except one who does hang out around the filter on his own.). The angel will swim around the lower area of that part of the tank, but I was worried it was too much current.

I had two of the crypt wendtii in the tank and the one that was the closest out of all my plants to the outflow 'melted', and I'm not sure if it will be coming back.. part of the green grass plant is consistently moved around in the current as well, and I'm sure that'll only get worse as the plant gets bigger, so this is why I was afraid the current may be detrimental to the plants.

But the sponge filter seems like a cheap alternative to switch to, which is why it's something I was willing to consider. I just didn't want a lot of loud noise, and a lot of things I've read online have made it seem like sponge filters were the loudest things out there. Not only would that be annoying for me, but I worried that wouldn't be calm and peaceful enough for the fish. Come to think of it though, by lfs has mostly sponge filters in their freshwater tank and they didn't seem too loud. I'm assuming theirs are probably over sized considering how they overstock the tanks.

So, if noise shouldn't be a problem, I'll start shopping for a sponge filter. :) I'll also move my heater. Now, should I be running both the sponge filter and my hob, or is it ok/better if I can find a way to stuff the sponge into the hob filter for a few weeks and then install the sponge filter. Or is the current on the sponge filter so low that I shouldn't have to worry about the two running at the same time? I also currently have a sock/stocking full of gravel from my tank before I switched to the sandy substrate, which I know will help. I was about to remove it since my tank has settled in and should be done cycling. (Everything has been stable with zero ammonia and nitrites), but I figured I might as well keep it if I'm switching filters.
 
#7 ·
Before switching to a sponge filter, why not put a baffle on your existing filter to cut the flow back (or restrict it to the back wall). I have simple baffles made from water bottles (an idea I picked up here) that work fantastic at reducing the return water flow on my AC70 HOB - and you just can't beat the price!
 
#8 ·
i recently tried adding a dual sponge filter to my 29 gallon tank, and used a Tetra Whisper 40 air pump. i couldn't seem to get any suction though. particles would float right by the sponges, and i couldn't feel any suction when i put my hand on it. i added back the HOB filter for now. and i was planning on experimenting with a single sponge filter, and see if that works.
 
#11 ·
Okay, just one last question. I figured I'd just revive this thread instead of starting a new one since it's on the same topic and only a couple weeks later. Hopefully that's cool..

I went to my LFS and went ahead and took the plunge on getting a sponge filter (and some julii corys!). They only had two types there, and neither were the Hagen one you'd shown me, Bryon. They had one brand with a BRIGHT blue sponge which I didn't think would look too lovely with the greenery in my tank, and then they had the Lustar Hydro sponges, which is also what they use in a majority of their tanks so they must think highly enough of them. They did not have one for a 30 gallon tank, so he suggested getting two that are for the 20 gallon tanks. I figured I'd just get one, set it up and see how I like it and go from there. Well, I like it so I'm probably going to switch to sponge filters!

On to the question -- first off, the filters are kinda big, I was wondering if, with a 28 gallon tank, I should indeed get two filters for 20 gallon tanks, or would I be ok with one for a 20 gallon and one for a 10 gallon. I have a tall fake bonsai tree which will do well to hide the larger filter, but I was curious if I could get by fine with a smaller one on the other side of the tank.

Second, I'm assuming I'm right in this, I should probably run the HOB and the sponge filter together for a little while to build up the bacteria on the sponge and then add the new sponge filter, right? Or should I just go ahead and take out the HOB and put in a second sponge filter? I know you guys had said to just take out the HOB and put in the sponge filter initially, but that was before I was planning on having two separate sponge filters. :p Didn't know if that changed things.

And lastly, I'm now wondering what would be the best position for my heater now. Just next to either of the sponge filters, or should I put one filter on each side of the tank with the heater in the middle?

Yay, today was fun. I hadn't tinkered with my tank at all for the last couple weeks since I've been so busy. I've rehomed the danio so I've just got 5 rasboras (going to add a couple more), the 1 angel, and my 5 corys and my snails.
 
#16 ·
Okay, just one last question. I figured I'd just revive this thread instead of starting a new one since it's on the same topic and only a couple weeks later. Hopefully that's cool..

I went to my LFS and went ahead and took the plunge on getting a sponge filter (and some julii corys!). They only had two types there, and neither were the Hagen one you'd shown me, Bryon. They had one brand with a BRIGHT blue sponge which I didn't think would look too lovely with the greenery in my tank, and then they had the Lustar Hydro sponges, which is also what they use in a majority of their tanks so they must think highly enough of them. They did not have one for a 30 gallon tank, so he suggested getting two that are for the 20 gallon tanks. I figured I'd just get one, set it up and see how I like it and go from there. Well, I like it so I'm probably going to switch to sponge filters!

On to the question -- first off, the filters are kinda big, I was wondering if, with a 28 gallon tank, I should indeed get two filters for 20 gallon tanks, or would I be ok with one for a 20 gallon and one for a 10 gallon. I have a tall fake bonsai tree which will do well to hide the larger filter, but I was curious if I could get by fine with a smaller one on the other side of the tank.

Second, I'm assuming I'm right in this, I should probably run the HOB and the sponge filter together for a little while to build up the bacteria on the sponge and then add the new sponge filter, right? Or should I just go ahead and take out the HOB and put in a second sponge filter? I know you guys had said to just take out the HOB and put in the sponge filter initially, but that was before I was planning on having two separate sponge filters. :p Didn't know if that changed things.

And lastly, I'm now wondering what would be the best position for my heater now. Just next to either of the sponge filters, or should I put one filter on each side of the tank with the heater in the middle?

Yay, today was fun. I hadn't tinkered with my tank at all for the last couple weeks since I've been so busy. I've rehomed the danio so I've just got 5 rasboras (going to add a couple more), the 1 angel, and my 5 corys and my snails.
I'll respond to this post here, and then do another post on the subsequent posts to avoid mixing things up.

Hydro sponge filters are super efficient. I have one in my 10g and cannot believe the amount of stuff that I rinse out of it each week, even compared to the sponges in the larger tanks. They are good sponge filters.

In the 28g I would stay with the single 20g sponge filter. If the water is "clear" then it is doing the job. We mustn't forget that the plants are doing the filtration (keeping the water "clean"), the filter is only there to gently move the water and keep it "clear" by filtering out particulate matter. If the tank water is clear, the sponge filter is doing its job.

You could run the two filters together. But in a planted tank, provided it is not overcrowded but balanced, I would just switch them. If you read my article on bacteria you will see that more beneficial bacteria live in the substrate anyway, and that is the important thing.

I try to place the heater next to the filter in small tanks so there is some water movement around it. Though in my 10g they are on opposite corners.

Byron.
 
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#13 ·
Yeah, I will say that they don't have a lot of mechanical filtration to them, but my snails seem to get any plant matter picked up, and I've got a sand substrate, so vacuuming up any other waste is easy. I've got corys on the bottom the clean up extra fish food too.. I think I've got all my bases covered. :p I wish I could add some shrimp, but I know those'll be eaten by my angelfish soon enough.

I know if you put a powerhead on the sponge filter you'll get some suction on the sponges. I'm debating on if I want to do that or not, but right now I'm happy with the set up as far as noise is considered. Usually people switch to powerheads because of the noise.. Plus, my air pump will be powerful enough to take care of both of the sponge filters, I've already tested that with a gang valve and another airstone.

This has got to be the cheapest filter swap I've ever done.
 
#14 ·
I know I'm sounding like a broken record, but filtration is not about moving lots of water (suction), it's about finely filtering the water. A sponge filter will not move large volumes of water, but water passing through the cell chambers get filtered pretty well. Also, a sponge filter is not a good mechanical filter, but is a respectable bio-filter. I actually prefer my AC70 HOB with a sponge inside (along with bio-media) and use cut water bottles as baffles for very little water disturbance....So it's a sponge filter in a box.
 
#15 ·
Yepp, I didn't have any high expectations as far as mechanical filtration. You can especially see that won't be the case with the sponge filters because a lot of the filters are the same size as far as the tubing and strainers, the only difference for larger tanks is the size of the sponge, which obviously would have nothing to do with increasing water movement.

I wanted to cut back the water flow for my plants and for my fish. My fish don't really go to the side of the tank where my filter's output is - and I'm going to go ahead and assume the HOB's water movement is why.

I did my best to set up a decent clean up crew. And with sand, the rest of the cleanup is super easy on my part, so I didn't really need a lot of mechanical filtration. I may need to work more when I'm siphoning out the tank, but I don't have a filter to clean up too much either.
 
#17 ·
This post relates to the issues raised in the last 3 before my previous concerning the water flow, mechanical filtration, etc.

A sponge filter is pulling more water through than you would think. It does not need powerheads, esp in planted tanks. The sole purpose is to move the water around gently, to disperse nutrients, keep the water clear, and prevent dead spots heat-wise; though this latter is actually un-necessary. Many have tanks with no filters that function perfectly fine and the fish are happy and healthy.

I rinse my sponge filters every week during the water change; the amount of gunk that comes out is amazing. These are superb mechanical filters, which is the only filtration you want in planted tanks. Of course they do some biological as well, bound to, as bacteria will colonize all such inviting surfaces. I rinse mine in warm tap water, always have. I do not need bacteria in the filter. That's what the plants are for.

If your tank water is clear, then the sponge is doing its job perfectly. I had a 10g set up with no filter for several months. I felt the water really wasn't clear, so I added a Hydro sponge. Amazing. Crystal clear. That's all you need with live plants and a balanced fishload.

Byron.
 
#18 ·
For the most part, I agree 110% and for the same reason I contend that the conventional UGF works just fine with an air pump vs. power heads in either direction. Just to clarify, I did not mean that the sponge filter was ineffective with fine particulate matter, I was more referencing it's (mechanical filtration) effectiveness for larger, messy fish.
 
#22 ·
Looking good. m That will keep the tank crystal clear after the initial settling period of a new tank.

I don't see any problem, but you might want to turn the air down a bit. Just to experiment.
 
#23 ·
I don't know how to turn down the air. Do they sell gang valves for 1 tube? I don't see anything on the filter itself to slow down the airflow, and I read that you can poke little holes in the tube to cut down on the air flow, but I found that makes the air pump noisy.

The fish don't seem to be bothered by it. They swim near it without any issues. And I think my plants are going to be happier because they're no longer swaying in the current. I can see small amounts of movement, but nothing drastic.

Checked my parameters and ammonia and nitrites are at zero, so no spike so far. :) Taking out the other filter seems to be no problem at all, at least so far - just like you said! I've still been keeping an eye on it just in case.
 
#24 ·
I don't know how to turn down the air. Do they sell gang valves for 1 tube? I don't see anything on the filter itself to slow down the airflow, and I read that you can poke little holes in the tube to cut down on the air flow, but I found that makes the air pump noisy.

The fish don't seem to be bothered by it. They swim near it without any issues. And I think my plants are going to be happier because they're no longer swaying in the current. I can see small amounts of movement, but nothing drastic.

Checked my parameters and ammonia and nitrites are at zero, so no spike so far. :) Taking out the other filter seems to be no problem at all, at least so far - just like you said! I've still been keeping an eye on it just in case.
I wouldn't worry. But to answer your question, you can get a dual valve for the airline. One connects to the filter, the other valve to a 2-3 inch piece of tubing with an old airstone. By adjusting the two valves, you have full air flow out of the pump with some going to the filter and the rest through the "bleeder" airstone.
 
#27 ·
For the plants you have, I would not fiddle with CO2. I know I am not a CO2 person, because as soon as you start adding CO2 you are setting up a new level of balance, and more of this and that means more to go wrong. My approach is to keep it simple. Just my thoughts.
 
#30 ·
so I have a large sponge filter in my 75 and a bio-wheel mech. filter. Could I get away with only having the large sponge filter and very few plants? the sponge filter is as big as a toddlers head.
In a well-planted tank a sponge filter would suffice, even a 75g. After all, many have planted tanks with no filter at all. As long as the fish load is balanced, this works. I would need to know more about your fish and plants to say definite yes, but it is certainly possible with just the sponge.
 
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