The Great Mechanical Filtration Experiment

[dw1305]

Hi all,

One thing is for sure, and that is enrage @dw1305 by using my filter as a syphon!

Consider me enraged.

Inspection shows discoloration, but certainly not clogged or full of detritus.

That is really the important thing. As long as the filter media is:

• Being bathed in dissolved oxygen rich water, and
• the water flowing out of the filter is still oxygenated?

That is all that matters, it doesn't really matter what the journey was.

cheers Darrel

 

[Aqua sobriquet]

I’m starting to believe what Darrel has been saying all along. The best solution is a sponge on the intake pipe.
I personally am not particularly impressed with the pre filter on my Biomaster. There’s bypass going on somewhere resulting in debris covering my bio media (Siporax). The water in my tank is clear and the bio media is doing its job, but the main body of the filter is getting dirtier than it should do in my opinion. In this respect my Eheim 350 with an intake sponge is doing a better job.

 

[Bradders]

I’m starting to believe what Darrel has been saying all along. The best solution is a sponge on the intake pipe.

My view from experimentation is its a good idea to have some mechanical filtration (intake pipe, pre-filter) but if you have a low bio-demand to high bio-media ratio then it becomes even less important. But, overall, I support mechanical filtration and Darrel's view.

I personally am not particularly impressed with the pre filter on my Biomaster. There’s bypass going on somewhere resulting in debris covering my bio media (Siporax). The water in my tank is clear and the bio media is doing its job, but the main body of the filter is getting dirtier than it should do in my opinion. In this respect my Eheim 350 with an intake sponge is doing a better job.

I assume you have Siporax in both the EHEIM and Oase?

 

[Aqua sobriquet]

Yes on the Siporax. The last time I looked it was still quite white in the Eheim and dirty brown in the Biomaster.

 

[dw1305]

Hi all,

I’m starting to believe what Darrel has been saying all along.

What do you mean <"starting to believe ..........">.

The best solution is a sponge on the intake pipe.

Honestly it is the truth, and the <"bigger the better">. Starting using the 12" x 4" x 4" Koi sponges was one of the best things I ever did.

I only started because <"Rainbow Koi"> is 10 minutes down the road, you get <"a lot of sponge for your money"> and I got too lazy to <"sew up any more foam sheets">.

cheers Darrel

 

[Bradders]

Yes on the Siporax. The last time I looked it was still quite white in the Eheim and dirty brown in the Biomaster.

I would say the dirty brown wins! 😀

My HEL-X13 goes in white, and gets brown over time. I took some out before summer (consolidation from 2 x 250 to 1 x 350) left in my wfies greenhouse and it went white again.

 

[PARAGUAY]

I used to really like those overhead filters as favoured by early aqua_one ( aquariums) Quite surprised they haven't been marketed for all aquarium general sizes, but could be done with a little DIY. You could do your mantainence in 10 or 15 minutes

 

[Aqua sobriquet]

I would say the dirty brown wins! 😀

I’m not so sure. I can’t help thinking it’s working more like mechanical filtration. Is the debris that’s starting to clog the pores helping or hindering the biological filtration? Siporax is very porous so I’m guessing a small quantity of it could support a lot of bacteria. Not so much though if the surface gets clogged? It’s certainly not an issue for me as there is more than enough for the tank it’s attached to. It could perhaps be an issue with a heavily stocked tank though?

Edit: They say this on the Sera site.

“Sludge deposits may cover the pores, which inhibits the water flow. An effective prefiltration, e.g. with the sera UVC-Xtreme, prevents this.”

 

[dw1305]

Hi all,

I used to really like those overhead filters as favoured by early aqua_one ( aquariums) Quite surprised they haven't been marketed for all aquarium general sizes, but could be done with a little DIY

Same for me. They are my <"filter of choice"> and always have been <"My venture into my new 760 ltr planted tank ."> - <"Ammonia test kit and Urea">.

I would say the dirty brown wins! 😀 My HEL-X13 goes in white, and gets brown over time.

I think brown is good, mine is the same as @Aqua sobriquet 's "white", but I'm assuming that is just because I don't have a big enough bioload to get a <"thick enough biofilm"> to grow to be visible.

I'd bet there is a <"species rich microbial assemblage"> on the media, but just a very thin film of it. Dissolved oxygen may also be relevant, with "complete oxidation" <"reducing the extent of the biofilm"> - <"Water Handbook - Aeration | Veolia">.

That is one of the advantages of floating cell media, it sheds excess biofilm. This is for an <"Membrane bioreactor - Wikipedia"> in wastewater treatment, but illustrates what I mean <"Z-MBBR">.

..... Depending on the type of wastewater and operating conditions, MBBR carriers develop biofilms with different thicknesses. Although biofilm remains relatively thin, there are applications where carriers can clog up completely due to the overgrowth of biofilm.

Carrier clogging also occurs due to inorganics precipitating on the carrier surface (i.e. “scaling”) or due to the physical entrapment of solids or foreign particles present in the wastewater.

In conventional MBBR carriers, biofilm clogging drastically reduces the available protected surface area of the biofilm. This affects process performance as well as the microbial community in the biofilm, where unwanted species may thrive and compete for valuable oxygen and substrates.

Clogging is definitely one of the potential issues with Siporax etc. This is from <"Aquarium Science">, someone who keeps fish at an <"insane stocking rate">.

I’m not so sure. I can’t help thinking it’s working more like mechanical filtration. Is the debris that’s starting to clog the pores helping or hindering the biological filtration? Siporax is very porous so I’m guessing a small quantity of it could support a lot of bacteria. Not so much though if the surface gets clogged? It’s certainly not an issue for me as there is more than enough for the tank it’s attached to. It could perhaps be an issue with a heavily stocked tank though?

They say this on the Sera site. ...... Sludge deposits may cover the pores, which inhibits the water flow. An effective prefiltration, e.g. with the sera UVC-Xtreme, prevents this.....

That one for me. We don't need <"thick and sticky" biofilms">, all I want entering the filter <"are dissolved gases">.

cheers Darrel

 

[Bradders]

I was just about to post an extract about pore clogging from AS! I know some think Dave is dubious about his plant views, but I think he is pretty spot-on with most aspects of technology-based filtration.

Clogging of Pores​

And the “porous” ceramic media, fused glass and natural stone have a problem even for pores larger than a bacterium. Nitrifying bacteria live inside a biofilm (which they create) and that has a thickness of around 50-300 microns (let’s say 200 microns average). So, a round pore inhabited by nitrifying bacteria is coated on all its internal surface by this film.

Which means that is a diameter of around 400 microns (almost half a millimeter) is occupied by bacterial biofilm. And then, enough space needs to remain for a good water flow through it. This means that a single pore needs to be larger than at least one millimeter (two is even better) in order to be efficiently occupied by nitrifying bacteria.

Also, let’s say a ceramic media with a large surface area will have a pore size on the order of 30 microns (one thousandths of an inch). A bacterium is 2 to 5 microns in size. So, a bacterium only must divide a few times to clog a passageway into some ceramic media. Bacteria can multiple every 30 minutes. Think about that for a while. The pores are just too small. They clog far too rapidly.

So the effective surface area of all media becomes the surface area over which water flows, not the surface area that nitrogen gas can somehow find its way to.

 

[dw1305]

Hi all,

I know some think Dave is dubious about his plant views, but I think he is pretty spot-on with most aspects of technology-based filtration.

Same for me. I think he is very good on <"microbial (biological) filtration">.

Because I'm a great believer in a picture being <"worth a thousand words"> .........

<"Stocking of an Aquarium">.

cheers Darrel

 

[Oldguy]

Starting using the 12" x 4" x 4" Koi sponges was one of the best things I ever did.
Used these about 35 yrs ago. Plastic pipe with drill holes pushed through the filter a rubber bung on the end and a power head on the top. Also used these as a pre-filter for a canister filter. I went down this route as it was good value for money. Still have some in storage in the garage roof.

 

[Aqua sobriquet]

I wanted to recharge the Purigen on the Eheim so I took this picture of the Siporax in it yesterday. Still quite white after 9 months.



I fitted a sponge on the inlet pipe of the Biomaster a few months back so I may start cleaning the Siporax in it in batches to see what happens.

 

[Bradders]

I wanted to recharge the Purigen on the Eheim so I took this picture of the Siporax in it yesterday. Still quite white after 9 months.

I fitted a sponge on the inlet pipe of the Biomaster a few months back so I may start cleaning the Siporax in it in batches to see what happens.

What sort of bioload do you have in your aquarium?

 

[Aqua sobriquet]

What sort of bioload do you have in your aquarium?

Low on the Biomaster and very low on the Eheim at present.

 

[JohnCooke]

This is an interesting thread!

I've been trialling the coarse 10ppm sponges in my prefilter on my Oase 600. This is on a heavily-planted and well-stocked 240 litre tank. Compared with my previous 2 sets of prefilter sponges (30ppm & 45ppm) these 10ppm prefilter sponges have led to a better, and longer-lasting, outlet flow. I don't have a sponge on the inlet.

What I don't know yet, of course, is the effect on the media inside the main body of the canister. I'll be checking before the end of the month.

It does strike me that these coarse, 10ppm prefilter sponges are a good bet when going on holiday; less likely to clog!

 

[dw1305]

Hi all,

It does strike me that these coarse, 10ppm prefilter sponges are a good bet when going on holiday; less likely to clog!

That is partially why I'm keen on larger and / or coarser foam blocks. If <"life intrudes"> they give you some <"wriggle room">.

cheers Darrel

 

[Little]

I’m deciding what PPI foam to use in my new custom build AIO.

The front section will be 72 litres and the back filter chamber will be 24 litres (25% of the whole 96 litres).

Tank will be bare bottom (well rocks and epiphytes).

I originally planned a complex lasagna style mix of decreasing PPI but after reading this thread…. I’m thinking the full space in course is the way to go.

I have some 15 PPI pond sponge and now think I could just use this for the whole chamber and put a water thin slice of fine sponge on the intake.

Thoughts?

 

[dw1305]

Hi all,

Tank will be bare bottom (well rocks and epiphytes).

I'd still have a thin layer of sand, it can be a really thin cosmetic layer, but personally I'm not a fan of bare bottom.

I have some 15 PPI pond sponge and now think I could just use this for the whole chamber and put a water thin slice of fine sponge on the intake.

Assuming that it is fairly easy to clean the sump sponges? I'd go without the intake sponge, or use a larger sponge, rather than just a slither, on the intake.

cheers Darrel

 

[Little]

Assuming that it is fairly easy to clean the sump sponges? I'd go without the intake sponge, or use a larger sponge, rather than just a slither, on the intake.

Should be very easy to clean.
Will be a comb weir so just need something to stop the shrimps all migrating to the filter part.
It’s the same in my current AIO. Had to go quite fine as kept finding dozens of baby shrimp in the rear sump each monthly clean.
We build these planted nice tanks but they just wanna go live in the filter.