What Should I Have In My 3 Stage Filter?

[Katch]

Just wondering what you guys think I should have in the back of my Nano Cube 24G.

I've put one sponge in the first compartment about halfway down, a bag of ceramic rings followed by a bag of charcoal followed by a few bioballs in the second with the powerhead and heater in the third.

Is this ok or should I sort it out before I cycle in to far?

 

[waterdrop]

Carbon and bioballs would not typically come to mind in the filter for a small tank. Carbon is a type of "chemical filtration" which is primarily kept on the storage shelf by experienced aquarists to be used to remove medications after they've been used. It can also be used to remove yellow tannins caused by wood and the occasional organic odor of unknown origin. Under typical circumstances carbon gets used up within 3 days and is ready to be tossed out. For this reason its not usually used regularly.

Bioballs I believe came about as a low cost way of filling very large "sump" filters where the cost of typical higher-surface-area ceramics would be prohibitive (part of the appeal of ceramics is that they can last virtually forever.) In a small filter I don't believe bioballs would be contributing to high surface area in a competitive manner, but that is just my opinion.

The purpose of ceramic rings is to slow down the water flow by breaking up the current into smaller streams going in random directions. It thus performs mechanical filtration by helping larger particles to drop out of the flow. It also provides some decent bacterial surface area due to its rough ceramic surface. It is meant to be first in the sequence. Ceramic rings work better in larger filters. In smaller filters they can work ok but it is good to realize that they are taking away too much biomedia space sometimes.

In your filter it sounds like the sponge is serving as the main biomedia and source of medium to fine mechanical filtration. Sponge is excellent at these jobs. It may be possible to increase the amount of sponge if other media are removed or you may want to consider adding a "fine mechanical" media such as poly-floss.

~~waterdrop~~

 

[Katch]

Compared to previous filters I've used (canisters etc) I'd consider the filter at the back of this tank to be quite large. Each of the three compartments is about 20" deep x 6" x 4"

I'll go ahead and put the other 2 sponges I have into the first compartment but I had read somewhere that they can end up causing a build up of nitrates. I'm still at a loss as to what to put in the second compartment for best results. I'll take out the carbon in a day or 2 (brand new fill so it can take out any unknown nasties).

The manual has this to say on the matter;

Built-In 3 stage wet dry filtration system discreetly hidden and providing the maximum space for tank inhabitants.

* Mechanical- Sponge filters trap detritus and free floating particulate matter.
* Chemical- Activated carbon bag removes dissolved organics and odour.
* Biological- Ceramic rings & Bio-balls provide the ideal environment for beneficial bacteria.

You can see why I am understandably a little confused...

 

[waterdrop]

My apologies Kstch, I read the initial description of your tank and only really noticed the word "Nano" which in my book used to automatically mean tanks of less volume than 10 US gallons. Looking back I realize you are talking about a tank of 34G/128L, which is considerably bigger!

Even more surprising is the volume of the filter trays you list: 20"x6"x4", which is a full 2 US gallons of space per tray! A relatively huge filter!

If this is correct then it returns bioballs to being a more viable option as one of the biomedia constituents. One thing to understand about what your manual has to say about filtration materials is that there is a fair amount of overlap among the functions. Many materials will perform mulitple of the functions but each material will be optimal at only one of them. The opinions you hear from hobbyists are based on years of trying to pick the best material for a given task.

Sponge stands out as a material that is quite good at performing both the biological (lots and lots of surface area liked by the autotrophic bacteria) and the mechanical (great a trapping particles and keeping them out of the tank.) Scale is also a factor. If you were to imagine for a moment a huge cement pool at a wastewater treatement plant and imagine it filled with bioballs.. it would look like a huge sponge in a way. Ceramics are mentioned a lot as media because a byproduct of the way they are made causes there to be lots and lots of microscopic cracks and crevices just the right size for bacterial biofilm structures to take hold in. The ceramics used are often a sintered glass (one characteristic of sintering is the ability to produce a uniform and controlled porosity in the surface of the material after it is cooled.) Often I think of the rough surface one finds in ovens that are used to fire pottery, if you've ever run your finger across that material when its cool.

Anyway, a bed of gravel made of this ceramic stuff also plays the kind of exceptional dual role that sponge does: it provides excellent biological growth surfaces but it settles (remember, as the pump pulls water through, the individual grains of gravel will naturally randomize into average separation spaces) nicely such that particles will not find a way to cheat and sneak back through to the tank. Ceramic rings just do this on a larger particle scale and their greater per-grain weight helps them better slow the higher speed intake water.

Polyfloss beds or mats are often used to trap fine particles as the last media before the water returns to the tank but of course one of the down sides to fine filtering is that the material will become clogged sooner and will be renewable a fewer number of times prior to needing replacement. Floss is tossed more frequently whereas sponges can go many, many years before they break down and shred, needing replacement. Ceramics can theoretically go a lifetime, however there are debates about the merits of cycling new material in at certain intervals to offset pores that might be clogged by biofilms that are no longer functional.

Going back to sponges, one of the design parameters that rarely gets discussed is that they all vary with respect to pore size, openness of pathways and final slipperiness of the finished material surface or of the surface after biofilms have attached. One of the most interesting talks I was ever frustrated to miss was a talk that was given about a new open-celled filter sponge material at our Raleigh Aquarium Society one year.. sounded like my kind of topic.

~~waterdrop~~

 

[Katch]

Thanks for all your input.

Slight typo its a 24G tank so still just over 100 litres. The filter is built into the back of the unit full height and about 3" back so all in all its about 3" x 20" x 20".

Still after some definitive advice for what to put in there. As is stands I currently have;

filter sponge in the first section

ceramic rings (small bag), topped by quite a few bioballs and then another sponge to keep it all in

last section just the power head and heater.

In an ideal perfect world what should I use - I don't mind ordering new media but I'd like to get it right first time.

Also is it worth using a Nitrate removing media and if so how long do they last before need to be changed?

 

[Gvilleguy]

I have a Fluval 205 canister filter, and I basically have four media positions:

Position 1: The water "falls" into the left half of the canister via gravity, and that entire 12" (approx). depth is covered by mechanical foam media. These foams pieces are easy to rinse in buckets of tank water.

Positions 2, 3, and 4: The water is then pumped up the right half of the canister through three baskets: (the water goes through in the order basket 1, then 2, then 3)

Basket 1 = Fluval "pre-filter" cylinder pellets: these primarily act as mechanical filtration, according to the instructions. Similar to what Waterdrop said about changing the direction of the water, slowing it down, and making the solid waste settle out.

Baskets 2 & 3: In these baskets I have Biomax ceramic rings specifically designed to grow bacteria, and also a different brand of small bio-pellets that are in mesh bags (I had them on hand and wanted to add more bio-capacity to the baskets).

If I ever needed to filter out medication used in the tank, I would then throw in a carbon media in basket 1 in place of the pre-filter.

That was a lot of words to say that from what I have read, you really don't need chemical media except for special circumstances, and you generally want mechanical media to come before bio-media. This keeps solid waste from mucking up the bacteria colonies that we want to keep happy and un-mucked!!

 

[waterdrop]

What is the water flow path? Could you outline how the powerhead works and the exact order of media types the water will flow through? Does the flow path seem to allow for the sponge to get fully used? WD

 

[Katch]

Using the image above -

water flows in the grill - down through the sponge - up trough the ceramic rings / charcoal / bioballs - down to the powerhead intake - up and out through the powerhead outflow into the tank.

 

[waterdrop]

Ok, that's a little better than I was imagining. And the shown media layout is what they suggest I assume? Sometimes its better not to stray too far from the suggested layout of a given design.

I'm not an expert but I might fault the design slightly in that the intake is high rather than low. I believe this tends to leave larger debris for you to gravel-clean-water-change out of the tank rather than having as much filter pickup as a low intake provides. I'm also tempted to think the ideal order would be ceramic rings right where the water comes in, with the bottom of that compartment having sponge, then bioballs in the top of the next compartment and sponge in the bottom of that one too. But again, the designer may have known better.

On the positive side this will provide a very large biological filter with plenty of volume I believe, which is excellent. The mechanical filtration should be quite good too and the space is such that it remains flexible for chemical filtration needs. On top of that it provides the extra feature of in-filter heating, so overall its quite good I think.

~~waterdrop~~

 

[Katch]

Thank you,

I'm going to get a bit more ceramic media then as the bag it came with is tiny (hardly fills an inch of the middle compartment).

Is it advisable to clean the filter media periodically - not all of it obviously - but should I say rinse one sponge then put it at the bottom of the filter every 2 months or so and do the same with a bag of ceramic. I imagine I will have at least 3 of each so always 2 fully cycled and then one rinsed out...?

 

[waterdrop]

Media unblocking recommendations are different depending on whether you are still cycling or have moved on to normal tank maintenance after you have fish:

If you are still cycling you want to leave the media alone as much as possible. The young bacterial colonies are fragile. Recent research in fact is beginning to show that bacteria build structure into their biofilms, forming channels to allow water to flow in a manner that maximizes their chance of survival. Disturbance of their biofilm work only forces them to start this process over in some respects.

This advice however does not mean we would sit by and allow a filter to become blocked. A large filter such as yours will not be likely to suffer this problem but many of the smaller, less expensive filters we see in the beginners section can block up quite quickly. Those blockages and the resulting loss of flow must be unblocked by a gentle squeeze or swish of the media in tank water (never tap water) just enought unblock them but obviously not wringing out a sponge or that sort of violent colony loss. Muck is good!

Once you have fish you will go through a process of watching your NO3 levels to determine if you need to modify the normal starting recommendation of once a month unblocking of your biomedia and other maintenance of your filter.

~~waterdrop~~

 

[OldMan47]

You have a good layout in your filter right now Kstch. By starting with a sponge you are keeping most nasty dirt out of the main biological filter section and that section is nicely filled with biomedia. That arrangement should serve you well once it is cycled.

 

[Katch]

Ok here's my final layout (as soon as the new media turns up).

First section filter foam topped with Fluval Pre-Filter ceramic rings

second section, lots and lots of Fluval biomax ceramic rings topped with bioballs

third section, 800 lph head and 100W heater.

 

[Gvilleguy]

I'm liking it, Kstch! Good job. Those pre-filter rings are nice - I bought a box and could only use 1/3 of it in my filter. So they will last me a LONG time at this rate.

 

[waterdrop]

Sounding good!