Build as big a filter as you can afford is my advice.

[Stan510]

I recently added at least 50% more media to my intank filter I made for the 240 gallon with lots of plants and Rainbows,loaches, and a mated pair of Angels. A difference that is showing.
Look in 40 years of having this tank set up or taken down..I've never kept fish and plants this way. Usually I had larger to large fish. No plants ever.
So,after running this tank..its been tweak,tweak,tweak,as Barney Fife would say. I now realize the happiness of fish keeping goes way up with large filters filled with biomedia. I see many people have sumps..and then cheap out on small bags of media. FILL IT!..OVERDO IT!...also go to home depot and get that 1,000 hour pump they sell sort of cheap. Those canisters? ugh. You really would be happier with Rubbermaids filled with 30 gallons of media and then trickles back to the tank ( not my set up!..but just one version of many) and water stays much clearer..water changes go from clearwater to pristine.
I just needed to get it out there. Big filters= success.

 

[AbbeysDad]

Filters just make water look clearer, but not any cleaner/purer. And larger filters merely trap more detritus longer that decomposes to pollute the water. It's just an illusion that water 'looks' better.
Beneficial biology will always be in proportion to the bio-load that's creating ammonia and subsequent nitrite. Since most established tanks have plenty of BB in the substrate, larger volumes of any commercial bio-media, merely thins the wallet. With plants, especially fast growing floating plants using ammonia as their N2 source, very little beneficial biology is required unless the tank is heavily overstocked.
The best water quality is only achieved with routine partial water changes of sufficient volume to replace/dilute the polluted water.

 

[JBAwrench]

I made my own above tank filter media box.
It is just shy of 7 feet long.
It works well.
I will snap a photo of it later today to show you if you would like.

 

[Stan510]

Nothing like that. Even as I got back to my weekly water change routine? I could see on day 7 the water was clearer and less slightly tinted then day 7's previously. I thought I had enough media for a long time..but since I had more room..I thought,go for it.
Nature uses huge filters..miles of sand and gravel. Water quality is much better than any pond with plants. Look at the youtube vids of springs in Florida or Brazil.
I still make the water changes. I have fish that like to eat a few times every day. I imagine with the filter I have now,and only tetras..I would see even better quality and could go a month easy before a water change. But,Rainbows get to be chunky near 5" fish that need food...
I get nobody wants to spend more than they have to. But bigger filters and pumps get you farther..

 

[EllRog]

Nothing like that. Even as I got back to my weekly water change routine? I could see on day 7 the water was clearer and less slightly tinted then day 7's previously. I thought I had enough media for a long time..but since I had more room..I thought,go for it.
Nature uses huge filters..miles of sand and gravel. Water quality is much better than any pond with plants. Look at the youtube vids of springs in Florida or Brazil.
I still make the water changes. I have fish that like to eat a few times every day. I imagine with the filter I have now,and only tetras..I would see even better quality and could go a month easy before a water change. But,Rainbows get to be chunky near 5" fish that need food...
I get nobody wants to spend more than they have to. But bigger filters and pumps get you farther..

You still have to do regular water changes to remove what you can't test for. Your waters appearance has nothing to do with why you're supposed to do water changes, its just a bonus that it looks clearer afterwards

 

[mbsqw1d]

This is a good read

Comparison of Different Biofilter Media During Biological Bed Maturation Using Common Carp as a Biogen Donor

This experiment analysed the operation of submerged and dripping biological filters with three types of filling: commercial fitting HXF12KLL (CF), two innovative polypropylene aggregates (PPA) and polyethylene screw caps for PET bottles (PSC). The experiment determined the time needed to reach...

www.mdpi.com

 

[Stan510]

AND...I aerate the water as high as possible.and found that plants thrive as well. None of "driving Co2" out. Now,a Co2 tank might be greater for plants only...but I doubt fish are long lived in those tanks..seltzer water can't be good for them.
Now saying "a bigger filter only makes the water look clearer" is ONLY true with a diatom filter...getting it clearer with more media means you've upped the water quality with bacteria. Like toilet water vs treated water. Bacteria,not chemicals do most of the job. Of course for drinking they sterilize the water..WITH CHEMICALS.
No,been at this too long to not see that success means a bigger and better filter.

 

[AbbeysDad]

Now saying "a bigger filter only makes the water look clearer" is ONLY true with a diatom filter...getting it clearer with more media means you've upped the water quality with bacteria.

No, not bigger filters...ALL FILTERS. Filters merely trap organic particles, making the water look clearer...but those particles decompose in there and pollute the water. The 'trouble' with bigger filters is that they are often left unserviced longer, making them nitrate (and other pollutant) factories.
What would actually be better would be a regular or smaller filter that was serviced frequently to get the crud out of the system so as not to decompose and pollute the water. Service a mechanical filter every 2-3 days to get the 'crud' out and you'd have better water quality...
Better still, as in nature, would be fast growing plants and a flow through system where fresh water continually flushed out polluted water...(no filter required).
I know bigger or more filters and/or media seems like a great thing, but not when you analyze it more closely.

 

[seangee]

Ammonia is converted to nitrite which is converted to nitrate in a fixed ratio. So once your system (which includes plants, substrate etc.) can clear the ammonia and nitrite there is no further biological benefit to be had. I have been moving to less filtration in all my tanks for the last few years.

In fact today I took the decision to remove the the filter from my newest nano (22G) altogether and replace it with a low powered surface skimmer with nothing but a sponge pad in it. Yes that is still technically a filter but all the fish in the tank need calm or still water and I am pretty certain the filter in this tank does very little, if anything at all, in terms of biological filtration.

 

[EllRog]

Ammonia is converted to nitrite which is converted to nitrate in a fixed ratio. So once your system (which includes plants, substrate etc.) can clear the ammonia and nitrite there is no further biological benefit to be had. I have been moving to less filtration in all my tanks for the last few years.

In fact today I took the decision to remove the the filter from my newest nano (22G) altogether and replace it with a low powered surface skimmer with nothing but a sponge pad in it. Yes that is still technically a filter but all the fish in the tank need calm or still water and I am pretty certain the filter in this tank does very little, if anything at all, in terms of biological filtration.

I'm just running sponge filters these days and finding it much better

 

[Stan510]

You are so wrong,I can't even start to understand how "less filter" makes a better Aquarium. Its out there thinking really. Those people who use small filters or no filters have very few fish per gallon. Plants alone don't need a big filter,no. They don't eat meat and make waste!
This thing you repeat wrongly that big filters "only make the water clearer" as if something is wrong with that and of course leaving out the trillions more bacteria giving an aquarium a big margin of error at feeding time or stocking levels.
I never once heard anybody complain "I made my filter too large and now my water quality is too high"..Not once.

 

[mbsqw1d]

It would be interesting to read some actual scientific representation on this matter; so far its a matter of personal opinion.
Do nitrifying (beneficial) bacteria make the most of having a larger filter with the extra accommodation? Or is it just supply and demand? There has to be a cut off. Having a huge canister filter for half a dozen neon tetra for example, is obviously unnecessary, and I would doubt that the full surface area available is taken up by BB, as there would not be enough ammonia and nitrogen to feed them.
In terms of having 'clear' water, then that is mechanical filtration only, and nothing to do with bacteria. I've had wonderful results at 'scrubbing' the water 'clear', from sticking a small powerhead in the corner stuffed with polywool, but I wouldn't rely on that alone to house BB needed for nitrification. Why? Well, just from other people's opinion tbh...

 

[Stan510]

Unless we are talking Diatom filters, then I do think a fine biomedia not only traps particles..but breaks them down into gas. A sponge does that. A really huge sponge with a pump will beat a small sponge on air.
I see some large sumps built where the owner put in minimum media..and wondered why his water would be slightly hazy. I told him a few months ago..you dont have nearly enough bio filtration in that sump. Sure enough,he put in much more and his water quality went up..same fish,same pump. Then,I took my own advice..I mean I thought it was good..but could see room for improvement.
I'm thinking too one day a UV light might tweak,tweak,tweak it up even more.

 

[AbbeysDad]

Unless we are talking Diatom filters, then I do think a fine biomedia not only traps particles..but breaks them down into gas. A sponge does that. A really huge sponge with a pump will beat a small sponge on air.

Beneficial bacteria in the bio-media of the fresh water aquarium is aerobic. To convert nitrates into nitrogen gas requires anoxic or anaerobic bacteria which is difficult to maintain in the highly oxygenated FW aquarium. This bacteria can't survive in any sponge filter so sponge filters do not break down anything into gas.
Check out Dr. Kevin Novak's research on anoxic biocenosis clarification baskets.

 

[Byron]

How we individually define "filtration" is important. Most people when they talk about biological filtration are thinking of the nitrifying bacteria/arachaea that take up ammonia producing nitrite, then others take up nitrite producing nitrate. That is as far as they go (think). The bacteria/arachaea that perform this will colonize at the level required to handle the ammonia (and subsequent nitrite) occurring within the system. They will not populate beyond this. So if filter "x" provides sufficient biological filtration there is absolutely no benefit in a larger filter or additional filters, because they cannot do more than what is already being done. And I am taking it as assumed that the fish load/tank size is balanced to begin with.

That is however only one facet of filtration. The next stage, changing nitrate into oxygen or nitrogen gas, is denitrification, and this occurs in the substrate by anaerobic (and possibly aerobic) bacteria that are different species.

Then there is the clarity of the water, which has nothing whatever to do with the above. The more media and the finer the media the water passes through, the clearer the water will be. But that has no connection with the biological filtration above.