What If?

[BBradbury]

Hello AA...

What if I had a tank that had been running for several months and decided I didn't want to use a mechanical filter system. Instead I replaced the aeration (gas exchange) the filter provides with a couple of air stones attached to air pumps. The bacteria living in the filter media takes in tank water and removes a tiny bit of the ammonia and nitrite from the wastes the fish and plants produce. But there's bacteria on all the surfaces inside the tank too. In place of the bacteria in the filter, I start a more aggressive water change routine and remove and replace, say 75 percent of the tank water every week.

Would the tank still be as healthy without the filter? Would it be healthier?

Just a thought. Wade in if you care to.

B

 

[Big Ben]

So many variables are missing that a definitively true answer can not be provided. It could keep some fish alive sure, quality of life depends.

 

[BBradbury]

So many variables are missing that a definitively true answer can not be provided. It could keep some fish alive sure, quality of life depends.

Hello Ben...

Well, I've replaced the only two things the filter system does, like agitating the surface water to allow oxygen to mix with the tank water and allow carbon dioxide to escape (gas exchange). And, I've replaced the little bit of dissolved nitrogen the fitler removes, with a large weekly water change that will remove a lot more dissolved waste. So, what else does the filter do?

Just wondering if I really need the filter.

B

 

[Nils]

I'm pretty sure that you should leave the filter on the tank, this removes ammonia, nitrate and nitrite and even though the beneficial bacteria will do some, it will not do enough to keep the tank healthy. It also depends on what kind of fish you'd be keeping. The filter also has lots to do with the circulation of water, and stagnant water is never good. You'll get a film on the surface, and the fish wouldn't be happy either.

Nils

 

[mikem691]

I'm going to say no because you won't have enough water movement to convert ammonia to nitrite and then to nitrate. Too many dead zones. Unless possibly if you did daily water changes.

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[BBradbury]

I'm pretty sure that you should leave the filter on the tank, this removes ammonia, nitrate and nitrite and even though the beneficial bacteria will do some, it will not do enough to keep the tank healthy. It also depends on what kind of fish you'd be keeping. The filter also has lots to do with the circulation of water, and stagnant water is never good. You'll get a film on the surface, and the fish wouldn't be happy either.

Nils

I'm using two larger air stones and a couple of larger air pumps at opposites ends of the tank for a while. There's plenty of surface agitation for gas exchange and will remove and replace 2/3rds of the tank water every week, to remove any wastes from the water. As long as the wastes don't stay in the tank long, the fish should be fine.

Thanks again,

B

 

[Caliban07]

Hello again B.

If you are convinced that the filters only purpose is to agitate the water surface and remove teeny amounts of dissolved nitrogen then why would you feel the need to adopt a more 'aggressive' water change routine? Why not just carry on with your usual routine?

Anyways, changing out 75% of the water just reduces the efficacy and efficiency of the water change and in the average sensibly stocked community aquarium it is just unnecessary. You could do what you suggested no problem because GENERALLY speaking filter media takes a good long while to get dirty with large water changes and as you quite rightly suggest the bacteria will colonise everywhere to nitrify toxic nitrogen waste. In a sensibly stocked aquarium with a sensible feeding regime, water changes of that size will eventually bring your tank water much more inline with your tap. Stable parameters right?

Now that's great IF you have good source water and you can guarantee it will stay good. In reality it just ends up becoming a Blatant and completely unnecessary waste of water. Especially if you plan to do the same with multiple tanks.

I get the feeling that your tanks are very overstocked and thus overfed B and that for you it is necessary to adopt such an aggressive water change routine. You must have run in to some serious problems early in the hobby for you to have come to adopt this philosophy. If you leave the gunk to fall on the bottom of the tank and don't remove it this would also increase the need for higher volumes of water to be replaced.

Why don't you give us the stocking of some of your tanks? I read one once that was terribly overstocked with live bearing fish. I never said anything mind. I'll see if I can dig the thread out.

To answer your initial question no you don't need a filter in theory but I've never had to clean an African cichlid tanks filter or an oscars filter, I'd imagine they get pretty nasty but yeah your theory of compensating for the filter by removing dissolved wastes before they can build up would work. But why would you? Is it because water is cheap and filters are not? Do you choose shop lighting because it is cheap and aquarium lighting is not? Do you choose to avoid fertilisers because fish poop is cheap and commercial fertilisers are not? Do you choose to stock live bearers because they are hardy and cheap and because discus and their needs are not? There's a great world of fishkeeping to be experienced out there B.

Anyway personally I would prefer to under stock, feed sensibly, siphon substrate, filter fine particles and dilute half of the tank volume every week. Now I don't consider that bad advice do you?


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[Mattyfelts]

I'm pretty sure that you should leave the filter on the tank, this removes ammonia, nitrate and nitrite and even though the beneficial bacteria will do some, it will not do enough to keep the tank healthy. It also depends on what kind of fish you'd be keeping. The filter also has lots to do with the circulation of water, and stagnant water is never good. You'll get a film on the surface, and the fish wouldn't be happy either.

I'm going to say no because you won't have enough water movement to convert ammonia to nitrite and then to nitrate. Too many dead zones. Unless possibly if you did daily water changes.

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agreed, 1) theres no way nearly enough biologic bacteria in tank, 2) you would be essentially running an uncycled tank then and haveing to manually remove ammonia because there wouldnt be enough bacteria, thus needing a 100% water changes everytime ammonia starts to rise or else in a few months you would have a considerable amount of ammonia.

 

[friscuba]

Your filter should be way more efficient at breaking down and reducing wastes than just the surfaces of the tank and objects in it. How about instead of using the toilet, you just do your business next to it then remove 75% of it every three days? You'll be experiencing quite a bit of nastiness in short order, your tank might not be that different depending on how fully stocked it is.

 

[BBradbury]

Hello Cal...

Some good points, for sure. I'll address the water issue. Since this is the most important for keeping fish and plants healthy. Yes, I have very good water and my fish haven't noticed a change in 11 years or so. But, the thing about water is the more it runs through a filter, the more it changes from what it was when it originally came out of the tap. You don't want water to stay in the tank too long, because as the water changes, so does the stability and it's ability to support the fish and plants. It's not a question of how many fish you have, it's how long has the same water been in the tank.

B

 

[Caliban07]

Hello Cal...

Some good points, for sure. I'll address the water issue. Since this is the most important for keeping fish and plants healthy. Yes, I have very good water and my fish haven't noticed a change in 11 years or so. But, the thing about water is the more it runs through a filter, the more it changes from what it was when it originally came out of the tap. You don't want water to stay in the tank too long, because as the water changes, so does the stability and it's ability to support the fish and plants. It's not a question of how many fish you have, it's how long has the same water been in the tank.

B

But water that has been in a 30g tank for a week with a shoal of neon tetra will be different at the end of the week than a 75g tank that contains 2 oscars. The oscars produce a significant amount of nitrogen waste, they require more food more often which means more nitrogen waste and they produce a significant amount of poop. If this is left to 'dissolve' on the substrate you would see the effects from your tests.

Surely you can see that what is in the tank dictates how much water is required to remove toxins. Practicing the same water change routine for both tanks will yield different water parameters at the end of the week. The tank of neons will remain closed to your tap water than the Oscar tank.

I have always said that keeping the tank water as close to your tap water as possible by week end is a good thing but the amount of water that is required to do this will vary with each set up due to variables such as stock, feeding regime, fert dosing regime etc etc.

C.


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[Big Ben]

But, the thing about water is the more it runs through a filter, the more it changes from what it was when it originally came out of the tap. You don't want water to stay in the tank too long, because as the water changes, so does the stability and it's ability to support the fish and plants. It's not a question of how many fish you have, it's how long has the same water been in the tank.

B

The only ways the water chemistry would change are if you left water sit in a tank overtime the O2 levels would lower along with chlorine evaporation and it would become harder since the water would evaporate leaving a higher concentration of minerals behind.

Water running through a filter does not change unless the filter has some sort of reactive media. Filter floss is not reactive to the chemistry of the water. Water running over filter floss will not change the water. The only case it could would be if there was a presence of nitrifying bacteria in the floss and either ammonia or nitrite in the water from rotting food or fish excrement that over time will be converted into nitrate.

Are you seeking a way to justify a high bio load (too many fish relative to water volume) that a filter along with a regular water change schedule can not maintain in the long run.

My advice is get a larger then neccessary aquarium, use a bare bottom aquarium and get sponge filters. A sponge filter will fulfill bio filtration and is dirt cheap. Even better get a canister filter or hang on back to help polish the water, that will reduce the frequency of required maintenance.

If you get a large enough aquarium, you can lower the frequency of water changes since it will take much longer for nitrate to reach a level requiring a water change.

 

[trennamw]

Will it be heavily planted?

My little betta tank has been far more healthy since the filter died. I used to do weekly 50% changes and still have high nitrates. A week after the filter broke I had dropping nitrates and no ammonia. After awhile there was zero nitrate, zero nitrite, zero ammonia ... With zero water changes. Just top offs.

That's in 3 gallons with an ozelot sword and floating pennywort. The pennywort went bananas after the filter broke.

My suspicion is the plants are using ammonia and the bacteria aren't really doing anything (as evidenced by the lack of nitrate). Because when there was a lot of nitrate and no ammonia the plants didn't clean the water or grow.

So I would want to experiment with a heavily planted, filter free tank with air stones and maybe some circulation, and no water changes, to see.


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[Mebbid]

It would work assuming that you stock the tank sensibly. Its just a throwback to before filters were made.

My question is why?

Filters are a godsend for this hobby and I honestly don't see a reason to eliminate them.

 

[FWFishTanks]

If you had an airstone in every corner, it would add some flow. You could run a bubble wall under some bio media or lava rock for biological filtration. That may prove to be a somewhat useful method, but it won't out do real filtration. Hope I helped a bit.

 

[Delapool]

Hello AA...



What if I had a tank that had been running for several months and decided I didn't want to use a mechanical filter system. Instead I replaced the aeration (gas exchange) the filter provides with a couple of air stones attached to air pumps. The bacteria living in the filter media takes in tank water and removes a tiny bit of the ammonia and nitrite from the wastes the fish and plants produce. But there's bacteria on all the surfaces inside the tank too. In place of the bacteria in the filter, I start a more aggressive water change routine and remove and replace, say 75 percent of the tank water every week.



Would the tank still be as healthy without the filter? Would it be healthier?



Just a thought. Wade in if you care to.



B

How would solid waste be handled? Gravel vacs or planted/break down naturally?

I'm thinking solid waste may be an issue and counter-balance the greater % of water changes. Depending on timing of filter cleans to remove solid waste.

Just thinking there, I could set up a small out pump with float valve inlet to have 'x' water changing each day. But then there is the particulate matter to deal with. Thoughts?

 

[BBradbury]

Hello Del...

Here's my take on a tank like this...

The filter has media and the bacteria living in the media, use a bit of the dissolved wastes that pass by, but not much. That's why any filtration system no matter how efficiently it runs, can't remove much of the waste in the water. The large water change, however does. I take out the old water with a lot of dissolved fish waste and replace it with new, treated tap water with no waste in it. The waste left in the old water that's left in the tank, dilutes to a safe level in all the new water.

If I remove the filter completely, replace it with a couple of air stones to still have sufficient gas exchange and increase the water change, I don't need the filter, because I've put in place something that will do it's job.

The large, frequent water change is the real filter and the air stone is the means of mixing oxygen into the tank water and allows carbon dioxide to escape.

B

 

[Mebbid]

Hello Del...

Here's my take on a tank like this...

The filter has media and the bacteria living in the media, use a bit of the dissolved wastes that pass by, but not much. That's why any filtration system no matter how efficiently it runs, can't remove much of the waste in the water. The large water change, however does. I take out the old water with a lot of dissolved fish waste and replace it with new, treated tap water with no waste in it. The waste left in old water that's left in the tank dilutes to a safe level in all the new water.

If I remove the filter completely, replace it with a couple of air stones to still have sufficient gas exchange and increase the water change, I don't need the filter, because I've put in place something that will do it's job.

The large, frequent water change is the real filter and the air stone is the means of mixing oxygen into the tank water and allows carbon dioxide to escape.

B

By dissolved waste the only thing that really comes into play is the nitrogen level.

It honestly seems like a lot of extra work for no real benefit. You would have to test the water very frequently as you presumably would be continuously cycling the tank and very frequent water changes would have to follow that.

It really seems to me that it would be a less stable system.

 

[BBradbury]

Hello Meb...

The nitrogen level would be low, because of the large, weekly water changes. There would be no time for wastes to build to anywhere toxic levels, before they were removed, making for very stable water properties. The small amount of nitrogen left, would be used by the bacteria that colonizes the substrate, plants, driftwood and other decorations and what isn't used is diluted to a safe level in all the new water. Large water changes take longer, but not much longer. When I get out the gear to change the tank water, I make it worth the effort by removing a lot of it.

I admit to not testing my tank water, because of the high volume of fresh water I flush through my tanks every week. I don't need to test it, I know as long as I faithfully remove most of the old water and replace it with fresh, it will always be safe for the fish and plants.

B

 

[Mebbid]

Hello Meb...

The nitrogen level would be low, because of the large, weekly water changes. There would be no time for wastes to build to anywhere toxic levels, before they were removed, making for very stable water properties. The small amount of nitrogen left, would be used by the bacteria that colonizes the substrate, plants, driftwood and other decorations and what isn't used is diluted to a safe level in all the new water. Large water changes take longer, but not much longer. When I get out the gear to change the tank water, I make it worth the effort by removing a lot of it.

I admit to not testing my tank water, because of the high volume of fresh water I flush through my tanks every week. I don't need to test it, I know as long as I faithfully remove most of the old water and replace it with fresh, it will always be safe for the fish and plants.

B

But, as I've pointed out before without testing you don't know what your parameters are. Without a well colonized filter then you will get ammonia. I just don't understand "why" you would go this route. I'm not denying the fact that it would work.. but still, I don't see the point.

Honestly, you would be better off running an under gravel filter. That way you would know that you won't have to worry about ammonia.