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Hypothesis: Different "types" of filtration and their potential


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I am not sure how to explain this, but I will start with a brief attempt with details at the end.  I have a potential experiment for someone who actually has a rack and the means to do this.  I have one tank and have essentially been slowly experimenting with filtration over different iterations of multiple tanks the past few years.

Backstory:  I often have issues with certain types of filtration and I've been trying very hard to find something I'm actually happy with.  Because of that I view filtration in a certain way and I'm not sure what the "final outcome" really is, but there are some things I've noticed.  Potentially this is just a cut and dry pros and cons for different types of filtration also.

The past few months I've been working with a few bigger projects. I have my work on the Tidal series of filters alongside setting up a new tank with sponges.  I cycled the tank using cycled media and unused sponge filters and ran the tank for over a month.  Because I had it available, I also added a ziss bubble bio filter.  This was mostly on there to have a place for "extra air" to go because I had a pretty strong airpump on the tank.

Here's what I think is worth testing:
A.  Performance of sponge filters based on an air pump marketed for the size of the tank compared to one marketed for double that capacity.
B.  Performance of a tank with 2 sponge filters compared to having one HoB (bare bottom tank is best to highlight this).
C.  Performance of a tank with a HoB sized to the tank in question compared to one that is rated for double that capacity.
D.  Repeat the test B with different types of substrates and compare to bare bottom tank performance.

Essentially, I think as a new hobbyist it's very easy to get stuck in the overfiltration side of things and often I find myself running double, triple the filtration that what a tank is rated for.  In my main display tank I removed a lot of extra filtration and that resulted in a pretty significant issue with detritus worms appearing.

On the second tank, I ran it with sponges.  I would find muck under rocks and I would find uneaten food on the bottom of the tank (bare bottom).  This is expected, but what surprised me was that I had assumed the slime I was seeing was from the tank cycling and it was a bacterial slime. After seeing this for 2 months without fail I don't think this is the actual cause. I think it was mostly just uneaten food that wasn't caught in the sponge mixed with waste. In the lower flow parts of the tank it deteriorated and turned into a type of mulm.

The tank had tannins from the IALs and this was on a tank running with 2 sponge filters and the added ziss bubble bio.  Flow on all 3 filters was pretty high and I was still seeing a lot of detritus on the bottom of the tank compared to the actual filters themselves. Under the wood, rocks, and IALs especially.

Yesterday evening I took that same tank and hooked up a Tidal into it so I could run carbon.  Within about an hour the entire bottom of the glass was clean, Tannins were gone, and the glass looked pristine.

My experience with a sand substrate compared to a bare bottom tank using this same HoB filter made me think about what that causes. If there was sand on the bottom of this tank the mulm would have something to "grab onto" so to speak and it's the type of thing where the more "rough" or "course" the substrate is, I think this encourages a certain type of behavior from the mulm.  This is what I mean when I say "performance of the tank".

Ultimately we all have our own goal for how the tank will look! Some mulm is fine for one hobbyist while others want a pristine tank for fry with lots of clean water.

It's an interesting dilemma, and I think one of the reasons I have struggled with sponge filters is simply because I see too much mulm when I use them.  If I was only seeing the mulm on the sponge I'd be happy with that, but seeing it on the bottom of the tank just makes me inherently feel like I don't have enough flow.

I apologize for the long post, but hopefully this makes some sense!

Edited by nabokovfan87
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On 7/12/2022 at 1:47 PM, WillC said:

Question for you, what media did you use in your Tidals?

I have used sponge (pond foams), the seachem sponge 2-3 at a time, filter floss when I need it, matrix, and then I have also used the fluval biomax from aquaclears.

Day to day right now, I run 2 sponges and then the bag of media that comes with it.  Once you fill it above a certain point it's just bypasses easily because of the water level on the HoB cavity.  If you want to see my setup, there is a bunch of videos and stuff in the other seachem tidal thread, here:


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I'd love to try this, but I don't think I have the space to right now. I may see if I can fit in one or two of these tests when I set up my new fish room. I do love a good experiment! I wonder if five or ten gallon tanks would be best to try these on for me... But I also wonder if different HOBs or sponge filters wouldn't have different results when compared HOB to HOB or sponge to sponge. 

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On 7/12/2022 at 7:30 PM, Emrie G said:

But I also wonder if different HOBs or sponge filters wouldn't have different results when compared HOB to HOB or sponge to sponge. 

I would love to test it specifically with something like an AC20/30 and a Tidal35.  I absolutely think things will greatly vary from one HoB to the next.

I think a 10G or 20L tank fits that, but the difficulty is having the "standard" filter along with the one that's hobbyist recommended and we all mostly use.

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