Sponge Filter Questions

[JAOF]

Hello people!
Good Morning.
This thread is started by me because I am in a great dilemma with my recently aquired Sponge Filters.
First of all let me present what I know-
1.They run on an air pump
2.They are efficient Biological Filters.

Now I am having some problems assembling the Sponge Filters.
What is the purpose of the clear pvc tube that tops the filter?
Is it an essential component?
Would it not work without the pvc tube?
The store that I bought the SF from wasn't using lift tubes but I was a complete noob about Sponge Filteration so I beleived that it is the way they are intended to be used. But my box contains a pvc tube,and I found after seeing some pics on the internet that it is topped on the Sponge Filter.
Is there any harm if I do not use it?
My tank has two Over the Tank filters running and I just wanted to add some more Biofiltration.
Thanks for any input.

 

[VWTDI02]

I have a sponge filter in my shrimp tank. It originally was missing the lift tube (clear plastic tube) but I grabbed some tygon tubing and made one myself. The only real difference that I've been able to notice was in regards to my duckweed. With the lift tube I get less surface water movement than without it. So right now if I pull off the tube, there is a larger hole in the layer of duckweed.

When I originally spoke with the guy at the store he said that the difference is pretty much negligible. I agree but it depends on the filter. The lift tube insures that you aren't pulling water from above. Assuming where the air exits is far enough down in the sponge, it shouldn't make much of a difference. What I mean is that if the air is entering the water above the sponge filter and you don't have anything directing the flow (lift tube) you won't pulling water into the sponge. If the air is being released lower in the sponge, the only place the water can come from is the sponge.

To sum things up, if the air being released is above the sponge, use the lift tube. If it is below/inside the sponge then it really doesn't matter.

 

[JAOF]

The air is released at the base of the Sponge. It rises up through the strainer and exits at the top of the sponge where the tube is meant to be fixed.

 

[JAOF]

Is this how it should be set up?
I think I'll remove the tube because the sponges are for Biological Filtration only.

 

[VWTDI02]

Is this how it should be set up?
I think I'll remove the tube because the sponges are for Biological Filtration only.

That looks good to me. I don't really understand your reasoning for removing the tubes. Either way u don't think it will make too much of a difference.

 

[Dolfan]

I would not remove the tube. It is required to help create the lifting action and pull water through the sponge. Otherwise the suction would be very weak and not as much water would pass through the sponge. The tube is there for a reason.

 

[VWTDI02]

I would not remove the tube. It is required to help create the lifting action and pull water through the sponge. Otherwise the suction would be very weak and not as much water would pass through the sponge. The tube is there for a reason.

If the air is being released at the bottom of the sponge as he says, water will still be flowing through the sponge and up the middle of the sponge. Any evidence as to why it would be "very weak"? I've run mine without the tube and it did just fine. Especially with his that releases the air ay the bottom of the sponge.

 

[Dolfan]

Because the sponge is only 3 inches tall or so. Without the tube, where the air is released from the airline and where it exits the top of the sponge is a very short distance. This means that the air bubbles don't come in contact and push a lot of water up, which is what creates the suction. With the tube in place, the water has a chance to contact and push 6-8 inches of water up and out, which pulls new water in behind it down low in the sponge. I don't know a way to prove this, but I promise you without the tube there is diminished suction. Why do you think the company would include the tube if it didn't do anything, that would be wasteful on their part. All sponge filters have some form of an elongated tube to help give the air bubbles lots of time to push water up. If the sponge itself was 6-8 inches tall, then maybe it wouldn't be needed as much, but even then using one would increase the flow through the sponge. When you say yours did "just fine" what does that mean? Yes it still filtered some water, but it probably wasn't operating at peak performance.

 

[JAOF]

People the Sponge is there just for a secondary Bio filter. Would it not serve as a BF if the Lift tube is there?
I am googling on them and this far I know that the tube is there just to create more suction and if I donot use the tube,the suction power will decrease but it would still work. My main motive of using the Sponges Without the tube is to keep a good colony of BB.

 

[JAOF]

I have removed the lift tubes. The thing is,as far as I know, without the tubes I am hampering my Mechanical Filteration,but my BF is unaffected. Lets see.

 

[VWTDI02]

Without the tube, the sponge filter will still work.

Having 6-8" versus 4" doesn't really matter. Granted there needs to be some room but the reason is that it prevents water from being pulled from above. That to me seams like the real function of the lift tube. Like you said the water does have 6-8" of vertical space to push the water but the flow rate remains the same as if it were 4". The speed at which water is going to come through the sponge is dependent on the amount of air being released from the pump. It doesn't matter how long it is being pulled for because it is still being pulled at the same rate; whether it be for 4" or for 8". The important part is that there is some room. The good think about the filter jaof is using is that it releases at the bottom of the sponge which gives it the length of the sponge to pull water from and travel upwards creating the suction. Once it passes the upper level of the sponge the air no longer matters since the suction is already going. On my sponge filter it is a bit different in that the air is released near the top of my sponge. Without having the tube on my filter, I might as well just have an air stone on top of a sponge because there is nothing creating the suction or controlling where the water is coming from.

 

[JAOF]

Exactly
The tank is a 90 gallon ( 3'*2'*2')
The air pumps are blowing 5 litres per hour.

 

[Dolfan]

I disagree completely. If you have less flow through the sponge then it is working less efficiently. If the sponge is in contact with 10 gallons of water per hour that would clean less water and impurities then if it were in contact with 15 gallons per hour.

A good analogy is think of the barrel of a gun. High power long range guns have a long barrel so there is plenty of force behind the bullet being concentrated for a longer period of time. This allows the bullet to travel faster and farther than if it had a shorter barrel. The only guns with shorter barrels are designed for short range and for ease of concealment/carrying.

I agree your sponge filter will still work, but just not as good as it could if you use the lift tube. Why do you want to remove the lift tube anyway? It doesn't hurt anything, and in fact it makes your sponge filter work better. I don't understand wanting to use any equipment at a diminished rate. Why not get the full potential out of the sponge filter. You wouldn't run your canister filter only filled up with half the media.

Here is a great link to an article that explains airlift and how it works...


Specifically pay attention to the 2nd paragraph where it describes how the air bubbles and water react and how the tube concentrates this force mechanic.

Here are some more links to forum threads where this same argument is discussed...

 

[JAOF]

Great Links Dolfan!
Thanks mate. Wont remove the tubes. They are on the filters and the filters are running.
Do your tanks run on Sponges too?

 

[Dolfan]

I use a sunsun HW-302 canister filter for primary filtration but I also have 2 additional sponge filters for extra filtration. That way I can move one of the sponge filters to my extra 10 gallon in case of QT or emergency needs and the filter is cycled and stocked with beneficial bacteria. Here is a link to the sponge filters I use...



I like them as they are super cheap ($4 for small, and $6 for larger size) and the fact that they have 2 sponges on each filter. This way you can remove one sponge and thoroughly clean it if needed, while the other sponge stays stocked full of beneficial bacteria. It's good to stagger the cleaning, doing one sponge every few weeks then alternating to the other sponge next time. Although with my canister filter I rarely need to clean the sponges as it does most of the mechanical work and is the primary filtration. I like the aeration from the air driven sponge filters too.

 

[Orion5]

I would not remove the tube. It is required to help create the lifting action and pull water through the sponge. Otherwise the suction would be very weak and not as much water would pass through the sponge. The tube is there for a reason.

This is correct. The lift tube serves two purposes: one to concentrate the force of the bubbles lifting water, and to separate the outlet from the intake of the sponge. If you eliminate the lift tube, there is much more likelihood that the water will exit the top and go right back into the sponge again, thereby neglecting much of the rest of the water in the tank. Basically, there is less current created by the filter.

 

[1971roadrunner]

+1 on dolfan, the uplifttube creates a mild siphoning effect to help pull water upwards. Nuff said.

 

[VWTDI02]

I disagree completely. If you have less flow through the sponge then it is working less efficiently. If the sponge is in contact with 10 gallons of water per hour that would clean less water and impurities then if it were in contact with 15 gallons per hour.

A good analogy is think of the barrel of a gun. High power long range guns have a long barrel so there is plenty of force behind the bullet being concentrated for a longer period of time. This allows the bullet to travel faster and farther than if it had a shorter barrel. The only guns with shorter barrels are designed for short range and for ease of concealment/carrying.

I agree your sponge filter will still work, but just not as good as it could if you use the lift tube. Why do you want to remove the lift tube anyway? It doesn't hurt anything, and in fact it makes your sponge filter work better. I don't understand wanting to use any equipment at a diminished rate. Why not get the full potential out of the sponge filter. You wouldn't run your canister filter only filled up with half the media.

Here is a great link to an article that explains airlift and how it works...


Specifically pay attention to the 2nd paragraph where it describes how the air bubbles and water react and how the tube concentrates this force mechanic.

Here are some more links to forum threads where this same argument is discussed...


https://forum.simplydiscus.com/archive/index.php/t-77257.html

The analogy about the gun doesn't really relate to the sponge filter because it is a closed system from the back end. You're also dealing with a projectile that is accelerating as opposed to water that is traveling at a constant velocity. Also one of the main reasons that long range weapons have the longer barrel is in order to increase the accuracy which is needed at such distances.

The big thing is that with the OP's filter, the air is being released at the very bottom of the filter. As a result, that same interaction between the water and bubble occurs but inside of the filter. This design is more beneficial in that it moves the interaction further down the filter. If you want to keep the analogy of the firearm, it would be like the bullpup design in weapons. It moves the barrel closer to the back of the gun in order to shorten the overall length. With a regular rifle/weapon, the breach is further forward so the barrel starts there as opposed to further back with the bullpup design. In essence, the point where air comes out of the air line is the breach. Since OP's filter is released at the bottom it is like the bullpup design. Most sponge filters release at the top of the sponge since it is easier to attach the hose there. Those would be like the traditional breach location and would need the tube in order to make sure that the water is coming through the filter and not from above the filter.

While that article does explain the airlift mechanism, it doesn't say anything about the length of the tube. My main point is that the rate that the air is being released is what determines the amount of water being pulled. In OP's sponge filter the air is released at the bottom therefore the lift tube is inside of the sponge which shapes the water column as it goes out of the filter. As we know, the air rises and pushes the water with it but it is at a near constant rate whether it be inside the sponge or 6" above in a tube. Below there is a link in regards to the rate that bubbles rise. It is a little complex but the important part to take away is that the bubble will increase speed until it reaches a terminal velocity as it balances friction with the increasing size of the bubble due to the reduced pressure. As noted this happens relatively quickly and it is common to just say that the bubble rises at a constant rate. It is similar to an object falling to earth in that it will reach a terminal velocity and no longer increase speed regardless of how long it is falling.

https://boards.straightdope.com/sdmb/archive/index.php/t-169129.html

Those other links don't really take into account where the air is being released. A lot of sponge filters release the air near the top and therefore the tube does have an impact as it prevents water from being pulled from above which would reduce the flow of water through the sponge.

To sum things up since this is going a bit off topic, with OP's sponge filter I think it would be fine to run it with or without the tube without having a negative impact. This is due to the air being released at the bottom of the sponge and as a result, the interior cage of the filter acts as the lift tube that forms the water column and therefore the flow. If you're running a filter that releases the air at the top of the sponge then you will need the tube in order to prevent water being pulled from above instead of through the sponge. Having a longer tube will not necessarily mean a faster flow as long as it gives enough space for the air bubbles to change direction and reach terminal velocity which is very fast.

 

[ricmcc]

Is this how it should be set up?
I think I'll remove the tube because the sponges are for Biological Filtration only.

Although they must, on occasion, be cleared of the matter that they have collected, suggesting that the also serve as a means of mechanical filtration to some degree; just a wee point, they are mainly bio filters, and good ones at that, I believe. So we both agree, and it would appear that I am merely posting in an effort to upgrade my typing skills But they to collect matter, nonetheless. best to you, rick

 

[1971roadrunner]

Type in for search," Images for sponge filters", I don't think there is a single one on there without a tube. When I built my fist wet/dry sump years ago I started with simple things like this to get me started and be able to move/skip past 100% fine tooth comb basics in filtration and get to build/set up venturI skimmers, advanced UV's, refugiums and UGJ systems so as to keep this hobby fresh and exciting. Oh, and to keep the fish better too. Getting overly caught up in the basics stagnates. Just a thought!?!?

 

[VWTDI02]

Type in for search," Images for sponge filters", I don't think there is a single one on there without a tube. When I built my fist wet/dry sump years ago I started with simple things like this to get me started and be able to move/skip past 100% fine tooth comb basics in filtration and get to build/set up venture skimmers, advanced UV's, refugiums and UGJ systems so as to keep this hobby fresh and exciting. Oh, and to keep the fish better too. Getting overly caught up in the basics stagnates. Just a thought!?!?

I'm not sure who you are talking to so this may be misdirected. If you are referring to my post then your post really doesn't say anything in regards to my argument but rather just that you have experience building/setting up equipment. Again, if this wasn't directed at me then I'm sorry but I wasn't really sure.

 

[1971roadrunner]

Not in the least, actually I learned a lot from it and have enjoyed your posts all along. I go to other places to research building things like I had mentioned above and they keep telling me things like I had just posted to keep me moving along. I really enjoy fishlore 'cause it keeps me educated in some of the things I maybe had missed and new advances too, eg. your post etc... The people with whom I some times allow to mentor me, whom like to push the limits, through a research/build are down right hostile at times and I'm so thankful for it.

 

[VWTDI02]

Not in the least, actually I learned a lot from it and have enjoyed your posts all along. I go to other places to research building things like I had mentioned above and they keep telling me things like I had just posted to keep me moving along. I really enjoy fishlore 'cause it keeps me educated in some of the things I maybe had missed and new advances too, eg. your post etc... The people with whom I some times allow to mentor me, whom like to push the limits, through a research/build are down right hostile at times and I'm so thankful for it.

Oh gotcha. I agree, threads can be great sources of information but it shouldn't be the only source. Just check Yahoo Answers and you'll see some pretty terrible advice. haha.

 

[1971roadrunner]

Ohhh No! I'll take a look but if you hear about a man jumping off the Brooklyn Bridge on the news...........keep up the posts, ttyl.

 

[JAOF]

Can someone tell me how often should I clean these Sponges?
I know they need to be squuezed in tank water but how often?
And how do I know they are dirty?
Will mulm stick on the outer surface?

 

[tocandesu]

Can someone tell me how often should I clean these Sponges?
I know they need to be squuezed in tank water but how often?
And how do I know they are dirty?
Will mulm stick on the outer surface?

I usually squeeze the sponges every water change

Sent from my Nexus 7 using Fish Lore Aquarium Fish Forum mobile app

 

[khloem]

hI everyone! I had a few questions regarding sponge filters used for bettas.
•do they have to hook up to a type of power filter? in my 5 gallon betta tanks I have top fin internal corner filters, and the flow is just too strong. so I honestly don't know how sponge filters work, if you someone can explain it to me, i'd greatly appreciate it! also, my one betta's fin is all torn up, and i'm wondering if the filter had something to do with it.
•are there any that you'd specifically recommend for a 5 gallon betta tank?
•is there a different type of filter you'd recommend for this tank? I just need one that i'm sure will never mess up his fins.

thank you!

 

[Aquaphobia]

I am far from an expert on this but I do use sponge filters in my betta tanks! They hook up to an air pump only and the air runs down into the filter. Then when the air goes out of the filter it has to be replaced by something and water is pulled into it through the sponge as a result. Anything floating in the water that's pulled in is trapped by the sponge and the nitrifying bacteria grow on the sponge as well so the ammonia that's in the water that passes through gets dealt with. I hope that description makes sense!

This is the kind that I use in my tanks:

Your filter could have been the cause of your betta's ripped fins, or maybe a decoration, or...something else. I don't really know. But here is a picture of my betta Sacha having a rest on top of his sponge filter to show you how safe they are. The air output is behind him, you can kind of see it in the reflection:

 

[khloem]

I am far from an expert on this but I do use sponge filters in my betta tanks! They hook up to an air pump only and the air runs down into the filter. Then when the air goes out of the filter it has to be replaced by something and water is pulled into it through the sponge as a result. Anything floating in the water that's pulled in is trapped by the sponge and the nitrifying bacteria grow on the sponge as well so the ammonia that's in the water that passes through gets dealt with. I hope that description makes sense!

This is the kind that I use in my tanks:

Your filter could have been the cause of your betta's ripped fins, or maybe a decoration, or...something else. I don't really know. But here is a picture of my betta Sacha having a rest on top of his sponge filter to show you how safe they are. The air output is behind him, you can kind of see it in the reflection:

thank you so much! I totally understand it now, and I think i'm getting two sponge filters tomorrow! any ideas of good brands for 5 gallon tanks?

 

[Aquaphobia]

I think, though I'm not sure, that at least one of the filters that I have was made by the Xinyou company. All of their filters are identified by the letters XY followed by 4 numbers. The ones I'm using right now though didn't seem to have any identifying numbers. I bought mine through Ebay where many sellers carry it but I found it also through Amazon. Just type "sponge filter" or "bio sponge" into the search bar and you'll find many different options

 

[Jomolager]

I have sponge filters as second or third filters in most of my tanks, except Betta's. They are too strong for them. Sponge filters don't work without a power / air pump of some kind. By the time you add up the price of both you can do better buying an appropriate filter for a 5 gallon tank got a lot less. Good luck yo you.

 

[Vulpes]

I use sponge filters as a main filter,IMO they are the best types of filters out there.I heard lustar is a good brand for sponge filters.I use XinYou too since they're the only ones I can find here,but actually any sponge filter will work.

 

[Jomolager]

I use sponge filters as a main filter,IMO they are the best types of filters out there.I heard lustar is a good brand for sponge filters.I use XinYou too since they're the only ones I can find here,but actually any sponge filter will work.

From what I understand quite a few professional goldfish breeders agree with you. You are in a good company.

The problem is, not being a breeder, and considering needs and requirements of each individual fish in my tank, I can state unequivocally that every male Betta I've ever had so far, disagrees with you. My Goldies are in total agreement with my Bettas. Lol.

Also, larger tanks require stronger filters and more media than sponge filters can offer, especially with Ryukins.

Welcome to Fishlore. Please keep posting and let us know how your pets are going.

 

[Vulpes]

From what I understand quite a few professional goldfish breeders agree with you. You are in a good company.

The problem is, not being a breeder, and considering needs and requirements of each individual fish in my tank, I can state unequivocally that every male Betta I've ever had so far, disagrees with you. My Goldies are in total agreement with my Bettas. Lol.

Also, larger tanks require stronger filters and more media than sponge filters can offer, especially with Ryukins.

Welcome to Fishlore. Please keep posting and let us know how your pets are going.

Thanks!!I will keep posting and my pets are doing well .

I agree that sponge filters can be too strong for bettas but I used adjustable air pumps and my bettas didnt have a problem with that,so it does depend on your air pump.

 

[Jomolager]

Not an expert, but I have never seen an adjustable air pump around here. I mostly use Whispers that are real basic

I saw that you live in Brunei, I suppose water must be rather expensive in your part of the world. I am curious, is fishkeeping a widespread hobby in your neck of the woods? Another question would be, where the products you use in fishkeeping, such as tanks, filters, fish food, etc are made.

 

[hollie1505]

You can buy sponge filters like the one above with two sponges. If you have the space, I'd definitely go for a doubler... twice the media for beneficial bacteria to live on

 

[Vulpes]

Not an expert, but I have never seen an adjustable air pump around here. I mostly use Whispers that are real basic

I saw that you live in Brunei, I suppose water must be rather expensive in your part of the world. I am curious, is fishkeeping a widespread hobby in your neck of the woods? Another question would be, where the products you use in fishkeeping, such as tanks, filters, fish food, etc are made.

The water here is actually not expensive...

Fishkeeping is quite common among the Chinese in this country,although they don't do much research and go by their beliefs :'(.

The tanks I have are all built by my local LFS,otherwise I would have to buy tanks from companies such as Boyu,which are usually more expensive.

The products in BruneI are made by various different companies.Aquarium equipment such as filters,air pumps and LED lighting are supplied by Boyu,quite a popular brand in BruneI and Singapore.HoB filters are actually rarely used in the aquarium hobby,the most commonly used filters would be internal power filters.

Commercial fish food are imported from popular companies such as Tetra,HikarI and Nutrafin.Tetra also supplies water care products,so does API.Medicines are provided by a popular UK company,Interpet,which also provides us with some aquarium equipment.

Sadly,water test kits are not available in this country,some are actually sold but in the form of strips and tablets,which are inaccurate.This has been a big problem for me,as I am forced to use bottled bacteria such as Tetra SafeStart to cycle my tank and it has also caused me to encounter many mysteries (e.g why my fish are dying,why are they stressed etc.) ,overall it was a horrible experience.

I thank you for showing interest in my country.BruneI is a very small but rich country,I do not plan to stay here though.I do plan to relocate myself in another country when I grow up,where there will be more products(ESPECIALLY TEST KITS) and a larger variety of aquatic animals(ESPECIALLY INVERTS THAT DONT COST $8 PER HEAD),so that I can advance in the aquarium hobby.

 

[Jomolager]

This is so interesting! Thank you.

 

[Vulpes]

This is so interesting! Thank you.

No problem

 

[Aquaphobia]

That is very interesting! I've wished I could get some of the types of aquariums available in Asia but shipping would be prohibitively expensive. They are nice though!

Back to the sponge filters, I run 5 small filters off of one, dual-output air pump. Instead of splitters I use gang valves which also allow me to adjust the airflow to each one which also helps. I keep them output to a gentle bubbling which doesn't seem to bother my creatures at all

Supposedly there's a way to install an airstone inside sponge filters to make it even gentler but I haven't been able to figure out how to do that with these.

 

[Jomolager]

That is very interesting! I've wished I could get some of the types of aquariums available in Asia but shipping would be prohibitively expensive. They are nice though!

Back to the sponge filters, I run 5 small filters off of one, dual-output air pump. Instead of splitters I use gang valves which also allow me to adjust the airflow to each one which also helps. I keep them output to a gentle bubbling which doesn't seem to bother my creatures at all

Supposedly there's a way to install an airstone inside sponge filters to make it even gentler but I haven't been able to figure out how to do that with these.

Picture please!

 

[Aquaphobia]

I tried to get a shot that included the valves and a good view of the surface agitation in Vlad's tank just in front of them. I probably should have shut off the plant lights, that camera overexposes everything anyway. Oh well, did my best!

Sorry for the messy airlines all over the place. I'm going to rework my betta corner just as soon as the rest of the house has settled down a bit. It's more important to me that everything work right now.

Also Vlad, getting in on the action

 

[Jomolager]

Thanks for the picture. It is the valves I am interested in. Where do you get them?

 

[Aquaphobia]

I thought any pet store would carry them but for sure on Amazon or eBay! Just checked, PetSmart has them too, with 2, 3 or 4 outlets

 

[khloem]

thank you so much everyone! my two sponge filters are coming tomorrow!

 

[fyshfuud]

I’ve been considering sponge filtration for my 40 breeder tank. I will be keeping fish that prefer very little water movement. honey gourami, peacock gudgeons, Bolivian ram

I’ve been trying to research sponge filtration. I’ve seen a lot of info about their benefits and how to service them; but nothing suggesting how to choose the air pump to run it or if multiple units are suggested to prevent dead zones?

Here are my questions so far...

1. How many gallons per hour should I aI'm for to filter 40 gallons? It’s a standard breeder tank 36x18x16. I want enough surface movement to be efficient,but not be uncomfortable for honey gourami to surface if they wish.

2. Do I get one sponge rated for 40 gallon or greater and stick it in one corner of the tank, or get multiple? Perhaps one for each end of the tank? Would 2 - 20 gallon rated sponges work as well or better than the one 40 gallon?

3. If I go the 2 sponge route; is it better to get a 2 line air pump, a one line pump with a splitter, or is it best to get 2 separate pumps?

I intend for the sponge to be my only filtration. I dislike the sound of hob filters, the cost and chance of leakage you get with canisters, and the internal filter I tried most recently is just far too strong and blows the sand everywhere. Others I have tried in past setups don’t seem to get the flow across the tank well.

Any advice is much appreciated.

 

[Old Salty]

I am running a large 2 port air pump, I think it's rated for 40 or 60 gallons, for 6 sponge filters in 6 1 to 2 gal betta tanks. Each line has a 3 way splitter. It's adjustable air flow in case it was too strong. You could try 2 filters and take one out if it's too much. I would also suggest going to a hardware store with the acrylic air pipe thing that directs the bubbles upward and getting a longer one the exact same size. This will carry the strong bubbles to the surface to dissipate rather than having them jostle your fish around. And if you don't have the air pump yet, I highly recommend finding one on Ebay.

 

[fyshfuud]

Old Salty Thanks. How far below the water surface do I want the longer pipe to be? Do you use air stones with yours or just let them make large loud bubbles? Does bubble size really matter?

 

[Old Salty]

Old Salty Thanks. How far below the water surface do I want the longer pipe to be? Do you use air stones with yours or just let them make large loud bubbles? Does bubble size really matter?

I have one bubble riser set right below the surface of the water, which I prefer. The others are all about 2 inches from the surface, which is alright. I have one taller tank where the bubble riser is about 4 inches from the surface, and that one I'd like to replace with a taller riser. It's a little rougher in that tank but not unbearable, I would like to replace it though. No air stones are necessary with the sponge filters I have, nor would I know how to even attach an air stone to it. The air is forced down into very tiny holes which produce the bubbles. If you can figure out how to attach an air stone, I think smaller bubbles is more aeration which is good. The only thing with these sponge filters is the tiny holes do get clogged about once every 3-4 months and you have to take them apart to clean the tiny channels, which isn't too bad. Of course the sponge has the bio filter so you'll just want to squeeze those periodically in dechlorinated water.

 

[Old Salty]

Also the bubbles aren't too loud because I don't have the air pump on full blast, which is why I really recommend it for fishes who don't like strong currents.