To filter or not to filter, that is the question

[Draco]

So in my years of keeping nanos and picos on and off, I've always modded a HOB filter to hold sponges, carbon and such.

 

Now Im restarting a 6 gallon tank, and debating on going filterless.

 

What do you guys think? I've never gone without a place for media. I have a wave maker for water flow. plenty of rock and sand.

[seabass]

IME, you'll be fine without mechanical and chemical media.  Personally, I often like running my tanks with just a protein skimmer; although I have a couple running without any filtration at all.  I've seen a number of successful filterless setups.  Even my tanks with HOB filters, are normally run without any media in them.

[Tired]

My pico seems fine without any sort of actual filtration. I use an empty canister filter for it, partly to add a bit more water volume, mostly so that the vibrations from the pump are outside the tank and therefore have no way to possibly bother the fish. I have stuck some activated carbon in there a couple of times, when something carbon-worthy had recently happened. Other than that, it's pure water flow, not filtration. 

 

You probably have a spare HOB lying around somewhere, right? I say, keep that spare. If you ever need to run activated carbon in this tank, just slap the HOB on with some carbon in it until the need is gone. 

 

[wiigelec]

I like to have some means of mechanical filtration to pick up the junk lifted from the scape after a good turkey bastering. Skimmer or HOB or canister or filter sock or whatever. Something easy to clean.

[jservedio]

There is zero need for mechanical or chemical filtration in a 6g tank if you are going to fill it up with coral. I agree with @Tired to keep an HOB laying around just in case you want to run GAC or to polish your water after scaping, but you shouldn't need one full-time.
 

I always start my tanks with filtration and every single tank I've kept, without fail, has ended up running with no chemical or mechanical filtration within a year or two. IME coral is the best filter you can have - they soak up all the nutrients that I can throw at the tank and then some, so filtration just ends up doing more harm than good.

[jservedio]

7 minutes ago, wiigelec said:

I like to have some means of mechanical filtration to pick up the junk lifted from the scape after a good turkey bastering. Skimmer or HOB or canister or filter sock or whatever. Something easy to clean.

It will naturally collect in the sump or back chamber and you can just suck it right back out with a turkey baster. However, that detritus is a really good source of nutrients and great home for pods. I purposefully let it collect in my 20g to feed my coral and other tiny life. This is what collecting all that detritus you blasted off your rocks a couple times a week looks like after 5 years (bottom pic). You can pull out as much or as little as you want depending on what the situation in your tank looks like.

 

[wiigelec]

4 hours ago, jservedio said:

It will naturally collect in the sump or back chamber and you can just suck it right back out with a turkey baster. However, that detritus is a really good source of nutrients and great home for pods. I purposefully let it collect in my 20g to feed my coral and other tiny life. This is what collecting all that detritus you blasted off your rocks a couple times a week looks like after 5 years (bottom pic). You can pull out as much or as little as you want depending on what the situation in your tank looks like.

 

Wow that’s a lot of gunk! Would you say this is more tolerable in a more mature tank vs. a newer less established tank, especially with no corals, or does it matter? I may still be stuck in the ultra low nutrients days.

[jservedio]

12 hours ago, wiigelec said:

Wow that’s a lot of gunk! Would you say this is more tolerable in a more mature tank vs. a newer less established tank, especially with no corals, or does it matter? I may still be stuck in the ultra low nutrients days.

Pretty much everything is more tolerable in a mature tank since things aren't changing all the time. As a tank starts filling up with rapidly growing corals, the nutrients for that growth need to come from somewhere. In bigger tanks, you generally have a lot more fish that are larger and can produce enough (or typically too much) waste to fuel that growth. In nano tanks (and especially pico tanks), you've got far fewer fish that are much smaller and the fish biomass to water volume ratio drops sharply. Oftentimes in smaller tanks with lots of coral, your fish and fish food just don't produce enough nutrients for your corals and you need to directly dose nutrients or find other strategies to get more nutrients to the corals that need them.

 

While your tank is maturing, you are probably going to fluctuate from too few to too many nutrients multiple times as you begin adding fish, as algae starts forming on your rocks, and you slowly add coral. You need to adjust your strategy fairly often as conditions change during those first couple of years because your tank is constantly changing - you need to make sure your nutrients never bottom out and at the same time, make sure they never get too out of control.

[Nano sapiens]

On 6/30/2022 at 8:52 AM, Draco said:

Now Im restarting a 6 gallon tank, and debating on going filterless.

So, there you go, lots of good advice ^^^

[Superdave]

Lots of good advice/perspective given above.  

 

As long as the corals and fish are doing well / looking good AND you are doing regular water changes you should be good to go without true filter.  

 

Surface agitation and no dead spots is key.  

 

I have a piece of floss at the over flow part of the my AIO tank and it gets really dirty in just a day or two.  I don't have any fish in there at the moment either though I do feed the corals here and there, but I take floss out of the water flow when I feed the tank.