Anybody running without filters?

[Django]

I'm sort of in between - in a 10 gal. tank I have an AquaClear 30 (adjustable from 10 to 30) at about 20 and I just have a sponge in there that I wash in tap water every week for mechanical filtration. I want the nitrifying bacteria to be in the tank with the plants, where all the action should be.

[dprais1]

Subscribed!

[PaulG]

I don't use filters. They cost money to run, buy and you need to service them.

You have to make sacrifices with fish load however. I'm ok with this.

[scapegoat]

Originally Posted by Dtitus1

Idk, I still wouldn't do it, the reason saltwater works without a filter (I still run one in mine regardless) is because your live rock builds up bacteria colonies that break down the waste.

Your plants aren't going to break down waste into usable nutrients, they're just going to use them, but if there's nothing to grow bacteria on to break down the waste it's just gonna build up and look nasty.

Now there should be some bacteria in your substrate, but this isn't really an efficient place for them to colonize in large numbers, so it would work to have no filter if you had incredibly low stocking in livestock, but still I'd just have a filter and more fish.

You're forgetting the immense surface area within a planted tank; all those plants. bacteria grow all over them. water flowing over their leaves is being filtered/cleaned all the time. Think of it as a symbiotic relationship between some coral and the algae that grow on them.

[Knotyoureality]

My 20g riparium is running without a filter or powerhead, heavily planted, heavily stocked with a juvenile BN pleco, a molly, six neon tetra, 3 amano, umpteen cherry culls, pond and malaysian trumpet snails (only a few huuuge ones, not enough food for them to reproduce thanks to the...) endless parade of females and fry from the resident black bar endler colony. Not a speck of algae, not even green dots on the glass. It gets a 10-20% wc every other week, more from habit than need. Substrate is fluorite with a scattering of aquarium gravel and small river stones, hardscape includes a variety of driftwood shards (3-4" long), a big hunk of dw for the pleco's cave and a large multi-branching bit of manzanita. No lack of surfaces for BB, especially when you add in the thick mats of aquatic roots from the riparium plants.

My planted vases (3g and under) are tech-free. Including a heavily stocked 2.5g vase with 8 cherry shrimp, a gazillion scuds, a male/female breeding pair of hybrid endlers and anywhere from 4-14 fry at any given time.

[Navyblue]

I think there is a lot of half truths being thrown around here.

Filters are useful for tanks without any means of nutrient removal, which are basically fish only tanks. It helps to break down ammonia to less harmful form (nitrate). I need to stress the word "helps" here, it is never a necessity. Nitrification can work pretty much anywhere, not just inside a filter. Tanks with means of nutrient export, namely planted tanks and some reef tanks, a mechanical filter is even less important.

A mechanical filter does not remove nitrogenous waste until you physically clean it, it merely breaks it down to less harmful form (nitrate) which will accumulate. Where as plants absorbs many forms of nitrogen compounds and remove them from the water. Altogether That is assuming the plants don't die and left to rot in the water. This is why it is possible to keep fish in a planted tank without water changes, without plants it is simply impossible. Therefore plant is a superior filtration to mechanical filter.

Fish poop on it's own is relatively harmless to fish. What is deadly to fishes is ammonia, which is constantly secreted by fishes through their gills. Fish poop and uneaten food is dangerous when they are decomposed by bacteria, which produces ammonia, which is deadly to fishes. Ammonia need to be dealt with as soon as they are available. They can be directly absorbed by plants.

As mentioned, nitrifying bacteria grows on all surface areas, and not just in a filter. A filter works by 2 ways. The first is to provide a growing surface for the bacteria. This is why filter mediums are porous objects, which has a high surface area to volume ratio. The second is the high water movement through the filter media heavily oxygenates these surfaces, a higher oxygen content can support a higher population of bacteria.

Both of those can be provided to a tank without actually employing an actual filter. The first though the use copious amount of substrate (which is typical in a planted tank), plant surfaces, or even porous rocks. In fact, unless you have a really huge filter, you are going to have a lot more surface area on your substrate than on your filter media. The second can be replicated through the use of powerheads (or even air stone), the higher the flow merrier, as long as your plants won't be uprooted by the flow and the fishes can take it.

Having a porous rock in a freshwater tank is different from the concept of using liverocks in saltwater tank. A liverock can have some denitrifying effect, deep inside it can form anaerobic regions that would house anaerobic denitrifying bacteria. This does not work in freshwater as freshwater carries a much higher oxygen content and anaerobic denitrifying bacteria can not achieve a meaningful population in a freshwater tank.

Also, apart from liverock, the popular methods for nutrient export in reef tank are algae scrubber and macro algae refugium. They work pretty much in a same way as using plant as a means of nutrient export in freshwater tanks. I personally keep reef tank with macro algae refugium for years without water change.

[extrame]

hi,
i run a tank with no filter and its been up for 16 months now.
its heavily planted and have a lot of fish, snails, and shrimps in it too

[scapegoat]

anyone running fitlerless hightech tanks?

would there really be a difference between high and low/dirt tanks as far as filter use? I mean, the filter does the same thing in either scenario.

[Wy Renegade]

So the point has been made that if enough substrate/surface area has been provided within a tank for bacteria to populate, then the process of breakdown can occur naturally within the tank itself rather than in/on a filter.

I would disagree with the notion that a freshwater tank has a higher oxygen content than a saltwater tank. Oxygen concentration has very little to do with dissolved substance concentration in water, it is mainly about temperature, therefore a fresh or saltwater tank with equal flow rates and equal temperature should have about the same concentration of dissolved oxygen. The primary difference is in the use of anaerobic areas within rock and substrate (often controlled by substrate depth). Certainly in a freshwater tank with a fine enough substrate there are anaerobic areas that support denitrifying bacteria. I personally think that this is simply an area of freshwater tanks that hasn't received much interest. Anaerobic is anaerobic, regardless of the oxygen content of the water, and if I can create anaerobic areas with a freshwater tank then those areas will support denitrifying bacteria.

The ratio of surface area on filter media vs. that of natural substrate and rock is also an often debated question. In reality, most modern filter materials have significantly more surface areas for bacteria colonization than the normal substrate that is included in aquariums, which is why they are significantly more effective at nutrient export. It that wasn't the case, everyone would still be using undergravel filters, as they take advantage of the normal substrate space available for bacteria colonization. The reason we've switched to modern HOB and canister filters is because they provide more surface area for bacterial colonization than most substrates and are therefore more effective a filtration. A quick good search in regards to surface areas of ceramic filter media or even bioballs bears that out.

All that said, there is no reason that running a filterless freshwater planted system should be any more difficult or any less successful than running a filterless reef tank.

Personally I think that flow rate (as it is in reef systems) is going to eventually emerge as one of the major factors.

[l8nite]

I'm interested now. My 110G has three filters on it right now (Eheim 2217, Fluval 405, and Fluval 403).

Would be pretty great if I could cut that down to one for just the inline CO2 & heater...

[PaulG]

Originally Posted by l8nite

I'm interested now. My 110G has three filters on it right now (Eheim 2217, Fluval 405, and Fluval 403).

Would be pretty great if I could cut that down to one for just the inline CO2 & heater...

What's your stock?

[l8nite]

Originally Posted by PaulG

What's your stock?

2x angelfish, gourami, red tail shark, 19 neon tetra, 7 black skirt tetra, 9 guppies, and 2 otocinclus

[dprais1]

Originally Posted by Wy Renegade

The ratio of surface area on filter media vs. that of natural substrate and rock is also an often debated question. In reality, most modern filter materials have significantly more surface areas for bacteria colonization than the normal substrate that is included in aquariums, which is why they are significantly more effective at nutrient export. It that wasn't the case, everyone would still be using undergravel filters, as they take advantage of the normal substrate space available for bacteria colonization. The reason we've switched to modern HOB and canister filters is because they provide more surface area for bacterial colonization than most substrates and are therefore more effective a filtration. A quick good search in regards to surface areas of ceramic filter media or even bioballs bears that out.

Every once in a while I search for some evidence to support the whole "high-tech filters are better than a sponge filter" theory but I have yet to ever find any.

[John K]

I never use filters on my tanks, just power heads for circulation. They're all set up as Walstad tanks -potting soil capped with gravel, lots of plants. I just tore down the first one - a 10 gallon that had been running for 3 years just fine. My largest is a 50 gallon with 5 Pearl Gouramis, 13 Rummynose Tetras, 3 adult Bolivian rams. Nitrates stay between 5-10 with only occasional partial water changes.

[Beer]

You have to have a decent plant mass for this to work.
To have no water movement at all, would have to be determined by the inhabitants and types of plants. some fish need water movement to be happy. Some plants grow too slow to do well without water movement to remove sediment and discourage algae growth. A good cleanup crew would be essential too (shrimp and a moderately small snail population). People mention water movement for nutrient dispersal, but I think an active fish population can help provide that. Nutrients aren't being depleted that rapidly in lowtech tanks.
I wouldn't recommend this though for tanks that don't get observed frequently. Just setting it up and leaving it to its own devices could be disastorous for the inhabitants.

NavyBlue, FYI fish don't actually put out waste from their gills (other than CO2). Gills are strictly for breathing. Look up the osmotic process, which is where GH and KH come into play for proper hydration and expultion of waste for freshwater fish (for salt water too, but salt water fish actually drink water constantly and also use the process to regulate internal salt content)