Do I have enough filtration

[tiger15]

So, as long as you have substrate and decor for BB to live, and you have a powerhead blowing water over said substrate and decor, you believe that 1. You don't need any mechanical filtration at all because in the wild fish usually live in murky water anyway, and 2. You don't need any bio media neither because you've got a powerhead blowing water over your substrate?

I must say that really is an interesting take on how to run an aquarium. Funnily enough though it would probably work in a lightly stocked tank maybe but I think i'd get a bit fed up of the water looking like crap all the time. You'd be forever vacuuming.

I've never used bio media in my filters for decades. In my show tanks, I use Penguin HOBs without installing biowheels for mechanical filtration only, which is necessary to keep the water clear for my enjoyment. Fish don't care. The reason I uninstall biowheels is to avoid reducing flow which is a trade off.

In my fry and grow out tanks, I have no mechanical filter, only air drive sponge filters. But I keep up with regular water change, including substrate vacuuming, in all my tanks which is the ultimate filtration.

I don't use power heads in most tanks as the HOBs are generally powerful enough to blow flow over the substrate. I only use power heads for my heavily stocked show tanks where more flow is desirable, but not necessary to keep fish alive. I have run the same tanks without power heads for years, and only recently install them to eliminate circulation dead spots. If gph is what one wants, wave maker provides the best bang for the buck.

 

[Joshuakahan]

I've never used bio media in my filters for decades. In my show tanks, I use Penguin HOBs without installing biowheels for mechanical filtration only, which is necessary to keep the water clear for my enjoyment. Fish don't care. The reason I uninstall biowheels is to avoid reducing flow which is a trade off.

In my fry and grow out tanks, I have no mechanical filter, only air drive sponge filters. But I keep up with regular water change, including substrate vacuuming, in all my tanks which is the ultimate filtration.

I don't use power heads in most tanks as the HOBs are generally powerful enough to blow flow over the substrate. I only use power heads for my heavily stocked show tanks where more flow is desirable, but not necessary to keep fish alive. I have run the same tanks without power heads for years, and only recently install them to eliminate circulation dead spots. If gph is what one wants, wave maker provides the best bang for the buck.

Sounds like a freshwater version of a FOWLR, if that worked, that’s pretty cool, never would’ve thought you could do that in freshwater

 

[viejafish]

Anything and everything inside of an aquarium is biological filtration media. If it has a surface for bacteria to grow on and oxygen is provided, the bacteria will do their thing. If whatever surface that bacteria chooses to grow on also happens to polish the water, then its even better!

The idea of dedicated bio media came with the invention of canister filters for home aquarium in the 80s. But long before it, UGF have been using gravel inside the tank as the bio media. Early power filters in the 70s provided solely mechanical filtration,, and only added bio filtration later in the form of bio foam, bio grid, bio wheel and other names in marketing to compete with canisters and one another. Vendors make you believe that their bio media is the best and without it, your fish will die.

 

[neutrino]

Anything and everything inside of an aquarium is biological filtration media. If it has a surface for bacteria to grow on and oxygen is provided, the bacteria will do their thing. If whatever surface that bacteria chooses to grow on also happens to polish the water, then its even better!

+1. Exactly.
Some are better than others, but besides all manner of plastic, sponge, ceramic, sand (including fluidized sand filters) and other marketed "bio" media, poly fluff and even carbon becomes "bio-media" if you leave them alone for a while. I've run very clean, zero ammonia and nitrite and low nitrate 50 and 55 gal tanks on power filters with nothing but poly fluff in them, once ran a filter with carbon as the "bio-media" for two years just to prove a point, and I've done something similar running filters with only gravel and fluff.

The 'can't have too much filtration' is one approach to it, and not wrong, similar to 'you can never do too many water changes'. But it's not the only valid approach, which I've proven over and over. At the other end of the spectrum are those who rely on plants, light stocking levels, occasional water changes, sufficient oxygen, and little else to maintain healthy tanks. There's not really a one size fits all approach to it, a lot depends on what works for you, what type of tank, how many and what kind of fish, your particular philosophy on it, etc.

 

[Joshuakahan]

+1. Exactly.
Some are better than others, but besides all manner of plastic, sponge, ceramic, sand (including fluidized sand filters) and other marketed "bio" media, poly fluff and even carbon becomes "bio-media" if you leave them alone for a while. I've run very clean, zero ammonia and nitrite and low nitrate 50 and 55 gal tanks on power filters with nothing but poly fluff in them, once ran a filter with carbon as the "bio-media" for two years just to prove a point, and I've done something similar running filters with only gravel and fluff.

So if someone ran a tank with high surface area rock, that rock would basically become freshwater live rock and all that would be needed is flow and water changes? I know live rock has other critters, but the main point of it is for BB. If that’s the case, why do shops not sell cycled rocks as freshwater live rock? You’d think they would make a killing on that like they do with real live rock.

 

[esoxlucius]

I think the common concensus amongst many hobbyists though is that no matter how much BB builds up on glass, substrate, decor, inside pipework etc etc, the main body of BB populations will always grow within the bio media compartment of whatever filter you're running on your tank. Safely tucked away going about its business. Could this now be considered a myth?

You guys, it would seem, have successfully turned this notion on its head, done away with the main filter part and let the other BB get on with the job, with great results.

But saying that, this is MFK and many people have big fish with bare bottom tanks for ease of cleaning, and no decor because of the potential danger of an expensive big fish injuring itself.

How much success would this filterless method have on a heavily stocked, bare bottom, decor free tank?

Maybe this method has indeed got a place but certainly not on all set ups.

 

[neutrino]

So if someone ran a tank with high surface area rock, that rock would basically become freshwater live rock and all that would be needed is flow and water changes? I know live rock has other critters, but the main point of it is for BB. If that’s the case, why do shops not sell cycled rocks as freshwater live rock? You’d think they would make a killing on that like they do with real live rock.

I assume by high surface area you either mean something porous enough or small enough units, large enough volume to amount much. What I've primarily done personally is run long term tanks using a variety of materials in filters, in concert with substrate, driftwood, plants, etc. I also have experience due to power outages of placing filter media directly in the tank and using the flow of a battery air pump to keep it active and to do enough filtration to keep fish well in reduced numbers in the tank (reducing numbers in my tanks by adding emergency tubs for some of them, etc.)

What I've seen done but not done in my own tanks are combinations of low flow, low filtration, few and typically smaller fish, a lot of plants, etc. But as esoxlucius says above, some alternate methods are for somewhat specialized tanks only, like low stock to water volume, lots of plants, etc. So my point was mainly that there's a lot of different ways to do it-- for example, we haven't even mentioned algae scrubbers-- and not a one size fits all rule for filters, media, etc.

 

[Joshuakahan]

I assume by high surface area you either mean something porous enough or small enough units, large enough volume to amount much. What I've primarily done personally is run long term tanks using a variety of materials in filters, in concert with substrate, driftwood, plants, etc. I also have experience due to power outages of placing filter media directly in the tank and using the flow of a battery air pump to keep it active and to do enough filtration to keep fish well in reduced numbers in the tank (reducing numbers in my tanks by adding emergency tubs for some of them, etc.)

What I've seen done but not done in my own tanks are combinations of low flow, low filtration, few and typically smaller fish, a lot of plants, etc. But as esoxlucius says above, some alternate methods are for somewhat specialized tanks only, like low stock to water volume, lots of plants, etc. So my point was mainly that there's a lot of different ways to do it-- for example, we haven't even mentioned algae scrubbers-- and not a one size fits all rule for filters, media, etc.

Ok, I can see a low stock, heavily planted tank working. I was just curious because it sounded similar to how I kept my reef tanks. I basically had 1.5lbs of live rock per gallon, good flow, lots of macro algae like dragons breath, “dirty” water corals like zoas , mushrooms , Xenia etc. and a good CUC. Never needed skimmers n sumps doing this type of setup. I’ve always heard that the majority of BB in freshwater is in the filter media and that the glass, gravel plants don’t provide enough surface area for it to work in freshwater setups. Sounds like it’s working for you. I won’t try it with my large bio load in my current tanks, but I might try it down the line with a different tank.

 

[esoxlucius]

I've often wondered what would happen in this scenario and at what point in the experiment would it all go south, if at all.

You set up 2 identically sized bare tanks, both with powerheads to move water around. The only difference is that in one of the tanks there is a filter with mech and bio, the other, no filter at all. Then you start the cycle with fish food for example, and you wait.

We know that the nitrogen cycle will start in both tanks and that eventually the nitrogen cycle will complete in both tanks. One will be relying on BB on the glass and powerhead, and the other will be relying on BB on the glass, powerhead and within the filter.

If the bio load is the same in each tank the BB will multiply to the amount of food source available. So that would mean you had the same amount of BB in both tanks whether one had a filter or not.

So now you put a fish in, the bio load goes up slightly but the BB in both tanks will also increase to cope and keep the cycle bobbing along. You add more fish, ditto, then more fish, ditto. Your BB increase and keep the cycle going.

Before long you find yourself running an aquarium which hasn't even got a filter in there!!

God forbid if you clean the aquarium glass at maintainance time or you switch the powerhead off so the food rich water isn't passing over the surfaces with BB on. And of course your water would be full of debris, but there's nothing stopping you from adding a simple sponge filter for mech only.

Of course there would probably be a point where if you had a heavily stocked tank that the surface area of the glass alone just couldn't house enough BB anymore and you'd finally crash the tank.

 

[tiger15]

There is a myth that when you clean the filter media, you should clean it with tank water, not chlorinated tap water, and always clean one filter at a time to preserve BB in the other filter. Nonsense. It sounds like BB have a conscience choice to live only in the filter media.

I never had problem cleaning all filters at the same time, and with chlorinated tap water as there are plenty of BB reserve else where in the tank to repopulate the media at no time. In fact, if you don't periodically clean the media, it can poison the BB bed by accumulation gunk and gunk eating micros that compete with BB for oxygen, and potentially turn anaerobic in a power outage. Canister filters are known to be vulnerable to anaerobic in power outage because it is not open to the atmosphere.