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The Great Mechanical Filtration Experiment

Hi Bradders,
I already done this test.
I have changed all my media in my filter with sponge similar to your blue sponge in the bio trays. With that, the filter worked fine until it started eliminating long stripes of detritus. Not many and the fish enjoy to eat them. Still I didn't like them and now I have a final layer of sponge similar with your orange Oase last sponge. That is doing a good job in collecting all of that floating stuff but then it's becoming clogged as fast as in the original setup.
Please keep in mind that all this happened having a prefilter fitted on top of the intake which stopped all big stuff to get in the canister and was weekly cleaned with the water changes.
So, my advice for you is:
In order to be able to touch less your canister, use those new 10 ppi prefilter sponges, but add as Darrel was saying, a minimum 30 ppi prefilter on the intake. That will be easy to be weekly clean with the water charges. This way you will not need to clean the prefilter in the canister so often but you will still need to give it a general clean every 6 months as before.
If you are not going to use a prefilter on the intake, then you will need to clean the canister prefilter every 2 weeks and open the trays every 4 to 6 months...
Good luck with your test.
 
Thank you for the insights @Gold Fish ! A couple of questions, so I understand.
Gold Fish said:
I have changed all my media in my filter with sponge similar to your blue sponge in the bio trays. With that, the filter worked fine until it started eliminating long stripes of detritus. Not many and the fish enjoy to eat them. Still I didn't like them and now I have a final layer of sponge similar with your orange Oase last sponge. That is doing a good job in collecting all of that floating stuff but then it's becoming clogged as fast as in the original setup.
Click to expand...
I assume you dont have an Oase filter? That correct? Also, what do you mean 'long stripes of detritus'?

Gold Fish said:
I have a final layer of sponge similar with your orange Oase last sponge. That is doing a good job in collecting all of that floating stuff but then it's becoming clogged as fast as in the original setup.
Click to expand...
I am working on a theory that filtration that gets clogged in relatively short spaces of time is due to it not being able to handle the load - well, not without cleaning periodically to restore that load capability. As an example, my Oase 250 is now 8 months old and the pre-filter was cleaned weekly when using 45PPI foam. However, an inspection over this weekend showed that the 2 x 20PPI foam and 1 x 30PPI foam in the internal unit was not clogged nor dirty - just a biofilm present. In short, still no need to clean. It would be interesting to understand your bio-load in proportion to your filtration to get an idea if you have any time.
 
Bradders,
No I don't have an Oase filter. Is an Eheim.
When you clean the filter, your water becomes dirty, but if you look closer you can see particles floating in it. Put 10 of them in a chain and you have my floating strings.
Regarding your filter, it will clog where is your finest filter. That can be the orange sponge or before at the matrix front face.(bottom of the lower matrix tray).
And finally, yes, it all depends on the bio-load and filter capacity.
 
Gold Fish said:
Regarding your filter, it will clog where is your finest filter. That can be the orange sponge or before at the matrix front face.(bottom of the lower matrix tray).
Click to expand...
Thanks, Gold Fish. Yes, the current experiment is as below, in terms of flow direction. I am not going above 30PPI foam.
  1. Pre-filter: 10PPI Foam
  2. Tray 1: HEL-X13 Media
  3. Tray 2: 20PP1 Foam
  4. Tray 3: 20 PPI Foam
  5. Tray 4: 30 PPI Foam
Gold Fish said:
And finally, yes, it all depends on the bio-load and filter capacity.
Click to expand...
I have done some calculations on bio-load, and 1 Oase Filter is around 55% capacity, just based on fish waste produced etc. Now, if my theory is correct, they should not clog too quickly - which seems to be the direction I am going at the moment, but it's too early to tell with the recent change of the pre-filter from 45PPI down to 10PPI. Effectively, I have 'opened the gates of hell' and allowed more detritus into the main unit with all the bio-media. It will either deal with it, or it will start to clog as it cannot deal with it. I am also keeping a close eye on water clarity.
 
Bradders said:
I am working on a theory that filtration that gets clogged in relatively short spaces of time is due to it not being able to handle the load
Click to expand...
Completely agree with this, with the proviso that the media used is suitable (not too fine), I think that a “sensible” balance between area and flow is required to maximise the efficacy of the filter
 
ElleDee said:
So, you are positing that if there's enough filtration capacity there won't be much residual mass left over to clog the canister? Just checking that I'm getting the hypothesis here.
Click to expand...
Correct, that is what I am aiming at. According to my math, the amount of plastic biomedia and foam should deal with 154 grams of fish with very clear water. I only have 80-100 grams of fish in my aquarium, which means it should (if this works) have no problems handling the load and clog very rarely. (Again, the theory is if you HAVE to clean your bio media every 3 weeks because it's clogged, then it can't handle the load).
fredi said:
Completely agree with this, with the proviso that the media used is suitable (not too fine), I think that a “sensible” balance between area and flow is required to maximise the efficacy of the filter
Click to expand...
I think (down to the basic math) I have the surface area and nothing is too fine, but flow is something I am also keeping an eye on. My filter only turns over 4-5 times the tank volume each hour. I have a good amount of surface agitation to assist with oxygen gas exchange but I agree that oxygen needs to keep getting into the closed-system canister.
 
Bradders said:
Correct, that is what I am aiming at. According to my math, the amount of plastic biomedia and foam should deal with 154 grams of fish with very clear water. I only have 80-100 grams of fish in my aquarium, which means it should (if this works) have no problems handling the load and clog very rarely. (Again, the theory is if you HAVE to clean your bio media every 3 weeks because it's clogged, then it can't handle the load).

I think (down to the basic math) I have the surface area and nothing is too fine, but flow is something I am also keeping an eye on. My filter only turns over 4-5 times the tank volume each hour. I have a good amount of surface agitation to assist with oxygen gas exchange but I agree that oxygen needs to keep getting into the closed-system canister.
Click to expand...
I think that you will find that “fine” media works ok initially(with sufficiently high flow), then clogs and efficiency drops off
Whereas “course” media lacks the surface area which “fine” media has, but (providing that flow is ok), maintains a more consistent efficiency, I binned my fine foam, I do use filter floss, although am getting through it quite quickly due to Panaque’s creating sawdust 😩
 
Bradders said:
Correct, that is what I am aiming at. According to my math, the amount of plastic biomedia and foam should deal with 154 grams of fish with very clear water. I only have 80-100 grams of fish in my aquarium, which means it should (if this works) have no problems handling the load and clog very rarely. (Again, the theory is if you HAVE to clean your bio media every 3 weeks because it's clogged, then it can't handle the load).

I think (down to the basic math) I have the surface area and nothing is too fine, but flow is something I am also keeping an eye on. My filter only turns over 4-5 times the tank volume each hour. I have a good amount of surface agitation to assist with oxygen gas exchange but I agree that oxygen needs to keep getting into the closed-system canister.
Click to expand...
Interesting. I always assumed that stuff would be leftover after the filter microbes did their thing; it would be transformed, but still large enough to clog a static filter. I don't really know though, I'm imagining it works like organic matter breaking down in soil, but it's not quite the same thing. I know you'll let us know.
 
Bradders said:
Thanks, Gold Fish. Yes, the current experiment is as below, in terms of flow direction. I am not going above 30PPI foam.
  1. Pre-filter: 10PPI Foam
  2. Tray 1: HEL-X13 Media
  3. Tray 2: 20PP1 Foam
  4. Tray 3: 20 PPI Foam
  5. Tray 4: 30 PPI Foam

I have done some calculations on bio-load, and 1 Oase Filter is around 55% capacity, just based on fish waste produced etc. Now, if my theory is correct, they should not clog too quickly - which seems to be the direction I am going at the moment, but it's too early to tell with the recent change of the pre-filter from 45PPI down to 10PPI. Effectively, I have 'opened the gates of hell' and allowed more detritus into the main unit with all the bio-media. It will either deal with it, or it will start to clog as it cannot deal with it. I am also keeping a close eye on water clarity.
Click to expand...
Using that arrangement, my bet is as follows:
You will end up cleaning the prefilter 2 or 3 weeks intervals because of plant materials clogging.
In 4 to 6 months you will need to clean the 30 ppi foam which will be clogged with detritus collected from the biological filtration.
I'm looking forward to see if my guess is close. 🤣😂🤣
 
ElleDee said:
Interesting. I always assumed that stuff would be leftover after the filter microbes did their thing; it would be transformed, but still large enough to clog a static filter. I don't really know though, I'm imagining it works like organic matter breaking down in soil, but it's not quite the same thing. I know you'll let us know.
Click to expand...
Gold Fish said:
I'm looking forward to see if my guess is close. 🤣😂🤣
Click to expand...
Yes, indeed, I will defo let you know. And I am also looking forward to finding out!
 
Little update for you @Bradders. I have 10ppi pre filters attached to the filter intake, 30ppi on the filter pre filter. The filter itself has 3 trays of K1 micro media and 2 trays of 30ppi foams. After about 6 months I opened it up, and despite cleaning pre filters regularly, the inside was full of gunge, explaining why the filter flow had substantially reduced. I’m not sure using only 10ppi as a pre filter is the way to go.
 
hypnogogia said:
Little update for you @Bradders. I have 10ppi pre filters attached to the filter intake, 30ppi on the filter pre filter. The filter itself has 3 trays of K1 micro media and 2 trays of 30ppi foams. After about 6 months I opened it up, and despite cleaning pre filters regularly, the inside was full of gunge, explaining why the filter flow had substantially reduced. I’m not sure using only 10ppi as a pre filter is the way to go.
Click to expand...
Very interesting.

So (as a comparison, and why I am trying to progress this little rabbit hole of a project!), what do you think it means that for eight months, I have used the standard Oase 250 configuration (mix of 30/45 PPI pre-filters, 1 Tray HEL-X13, 2 Trays 20PPI Foam and 1 Tray 30 PPI foam), and my last check shows that none of the inner trays were dirty/clogged and my flow has remained at the 500 - 600 L/per hour mark since it was purchased? (Bar pre-filler cleans).
 
Bradders said:
Very interesting.

So (as a comparison, and why I am trying to progress this little rabbit hole of a project!), what do you think it means that for eight months, I have used the standard Oase 250 configuration (mix of 30/45 PPI pre-filters, 1 Tray HEL-X13, 2 Trays 20PPI Foam and 1 Tray 30 PPI foam), and my last check shows that none of the inner trays were dirty/clogged and my flow has remained at the 500 - 600 L/per hour mark since it was purchased? (Bar pre-filler cleans).
Click to expand...
I think it might be an aging thing. When I first changed to the bio media I have now (from bio home) it would happily run for 6 months, and when I opened it up it was clean. Not this time though. It’s almost like it slowly approaches a tipping point. Current media has been in for about 18 months.
 
hypnogogia said:
I think it might be an aging thing. When I first changed to the bio media I have now (from bio home) it would happily run for 6 months, and when I opened it up it was clean. Not this time though. It’s almost like it slowly approaches a tipping point. Current media has been in for about 18 months.
Click to expand...
That is interesting. So your working theory is the age of the foam itself after prolonged use? i.e. the older it is, the less it will effectively deal with the load before clogging?

That is implying (if we are talking about the foam) that one of three things could potentially be happening.
  • The foam surface area is breaking down, meaning there is less of it, so therefore gets clogged quicker.
  • The bio-load in the aquarium has changed (increased) over the 18 months placing more load and therefore clogging quicker.
  • A mixture of both the above.
 
Bradders said:
That is interesting. So your working theory is the age of the foam itself after prolonged use? i.e. the older it is, the less it will effectively deal with the load before clogging?

That is implying (if we are talking about the foam) that one of three things could potentially be happening.
  • The foam surface area is breaking down, meaning there is less of it, so therefore gets clogged quicker.
  • The bio-load in the aquarium has changed (increased) over the 18 months placing more load and therefore clogging quicker.
  • A mixture of both the above.
Click to expand...
There’s a 3rd option, which is that the biofilm is getting thicker and in my gentle cleaning in aquarium water hasn’t been removed (as intended) until eventually it’s just got too much. The gunk wasn’t just in the foams, it was also in the K1.
 
hypnogogia said:
There’s a 3rd option, which is that the biofilm is getting thicker and in my gentle cleaning in aquarium water hasn’t been removed (as intended) until eventually it’s just got too much. The gunk wasn’t just in the foams, it was also in the K1.
Click to expand...
Yeah, I was thinking about that as well. It's too much hassle, but the only way to prove that would be to replace just one foam with a new one (i.e. keeping all the other bio-media untouched) and see if that one new foam does not clog at the same rate. But that depends on your loading and how much it already relies on that foam being populated with bacteria.
 
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