About filtration

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Re: About filtration

Post by Bas Pels »

Basically, you want this filter to carry your rockwork. That is, rather heavy stones.

If I look at the plastic, I wonder whether I woult trust this to carry say a 5 kg (some 11 pounds) stone.

I myself use styropore plates (sold for insulation) of 2 cm thick for precisely this purpose. I use tiles over them in order to keep them from floating, but these tiles also protect the styropore from any rocks
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Re: About filtration

Post by Viktor Jarikov »

To me it sounds like you will have problems vacuuming the substrate and getting all the crud out. If you will have a layer of sand, I am not sure why you'd need an additional weight-distributing / safety contraption.
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Re: About filtration

Post by Boris »

Viktor Jarikov wrote: Wed Mar 04, 2020 2:51 pm To me it sounds like you will have problems vacuuming the substrate and getting all the crud out. If you will have a layer of sand, I am not sure why you'd need an additional weight-distributing / safety contraption.
As far as I am aware sand is not considered a sufficient support for heavy rocks. The rocks will settle on the glass bottom creating point loads.
Yes, it will be difficult to vacuum under the rock piles in any case?
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Re: About filtration

Post by Viktor Jarikov »

In my mind I thought the fish are not diggers (perhaps I am wrong) and that you'd be lifting the rocks and vacuuming under them and setting the rocks back on the sand surface.

If you think of a more permanent installation, then perhaps you are right and you could set up tiles under the rocks, with or without the styrofoam mentioned by Bas, but he and other "substraters" should know better... because the last time I used substrate in my tanks was a decade ago... and even then I have never used sand, always fine or medium gravel. I have never bothered with any weight distribution of the heavy furniture.

If I am not mistaken, the bottom glass panes of small to medium (or all?) fish tanks are tempered. They can withstand a LOT of point load. Hit it with a hammer almost as hard as you can, you won't break it or will be surprised at the force you will need to finally break it... or such is my experience anyway.
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Re: About filtration

Post by Boris »

Somehow I had missed Bas reply.
I don't have access to large rocks so I will stack smaller ones in piles to create hidy holes.I have used styrofoam before but had the problem of it floating.
I'll see what I can find in the way of tiles?
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Re: About filtration

Post by Kilo_SSK »

Speaking of filtration, if I'm not mistaken, room temperature and sunlight exposure play a role in the speed at which flora develops in a fish tank, and thus, in the quality of filtration needed. The thing is that right now, I've only owned a fish tank in a room that doesn't get much sunlight, but I was planning to move to one of these flats on the Costa Blanca by late 2021/early 2022, and I've never had to care for a fish tank under that climate.
Should I be careful about something in particular, or would it be possible to keep filtrating the water of said tank at the same rate as usual?
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Re: About filtration

Post by Bas Pels »

if the tank gets too much sun AND there is enough plantfood in the water - this water might get green. Resulting in 0 visibility.

You better keep the sun out of the tank.

Further it is warmer there, but that only implies other species kept.
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Re: About filtration

Post by Jools »

Leave it, a siphon will be able to remove built-up debris if you wish. If you were going to put something under it, perhaps small rounded stones like you would use in a garden path or driveway?

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Re: About filtration

Post by TwoTankAmin »

I am a huge fan of Mattens. I have 3 tanks which rely primarily on them. Almost as much, I like the Poret foam cubes. This is a brand and I am sure there are other brands as good, I just ended up using this one.

The hardest thing I had to learn about using massively pored foam filter media was that it does a better job of mechanical waste processing than floss. I use almost exclusively the 20 ppi foam. 10 ppi is great for intake pre-filters or in canisters with more than two layers/baskets of media. Higher ppis clog pretty fast and are best used in shrimp and fry tanks, imo. I came to the Poret Mattens and cubes because I am noe in my early 70s and the work load of 20-25 tanks had been getting more difficult in the recent years. The Poret made filtration a lot easier to keep clean and maintain without sacrificing water quality which was my goal. At one time I had over 26 running AquaClears, today I have just 14 and I plan to reduce that number in the next few weeks.

While I will not argue that a planted substrate is one of the best "filters" one can have, they are not always possible. Nor will I argue against the importance of adequate oxygenation in promoting a healthy tank. However, I have never seen evidence of an oxygen shortage in any of my tanks including the 12 or so tanks with no plants with some of them also being bare bottom.

Big foam filter media will tend to do a fair amount of denitrification and still not result in water which is short on oxygen. I do not need to do all sorts of complicated testing to know this. I use these filters in tanks where I keep Hypancistrus species breeding and growing out. I have a lot of Xingu river fish and they live in water temps from the low 80s F to bouts of time at 90F+. This water temp tends to hold less oxygen than cooler water. But the fish have a need for high oxygen levels. My plecos do not die very often, do grow nicely and do reproduce successfully, QED the water must be OK in terms of oxygen levels being adequate and nitrogen levels being almost absent (i.e. not testable without expensive lab equipment).

The other thing it took me a while to learn was that filtration and circulation in a tank are not the same thing. For most in the hobby, their filter(s) adequately oxygenate the water. Moreover, as noted above, the bacterial colonies will ultimately size to the available bio-load. Therefore, if there is insufficient media/filtration to handle the nitrogen, the bacteria will colonize in other places. In substrate, under rocks and wood or other decor, they will establish and multiply. And they will colonize in the greatest numbers where the things they need are most available, i.e where flow/circulation delivers them.

Rather than trying to overpower a filter to get the desired level of circulation, it makes much more sense to divide that job between different pieces of equipment. A few small pumps and/or powerheads can insure that the water in a tank gets adequate circulation rater than a single large device which might blow some fish out of the tank.

Things can circulate pretty fast. I have seen this in my 55gal. Altum angel tank which has a digital monitor that continuously reads TDS/Conductivity, Temperature and pH. Between water changes the pH, targeted to be 6.0, tends to creep up towards 6.5 Sometimes mid-week I will add muriatic acid to the tank to drop the pH. I have actually a few times dropped the pH by close to one full point (1.0) and seen this happen on the monitor in about 5 minutes or less. I do dose the acid all across the surface rather than in a single place. (Filtation on this tank is 2 AC 200s, and air driven 4x4 poret 20 ppi and a large ATI sponge.)

Finally, there is one other consideration regarding ammonia and planted v.s. non-planted tanks. The plants take in ammonium (NH4) and the bacteria prefer ammonia (NH3) which is way more toxic. Even in a higher pH tank most of the Total Ammonia (TA), which is NH3 + NH4, is in the form of NH4. However, it is possible to remove virtually 100% of TA if one removes exclusively one or the other form. As soon as one form is removed, the remaining form converts partially and restores the balance for that water's specific parameters.

Plants can consume NH4 way more rapidly than bacteria/archaea can consume NH4. However, aquatic plants are covered in nitrifying bacteria. Moreover, some plants will transport oxygen down and out through their roots to turn an anaerobic space aerobic which encourages the colonization of the nitrifiers. So, no matter how many plants may be in a tank, there will still be some amount of nitrifying bacteria at work. On the other hand, it is possible for a tank with no plants or algae and even no substrate to process ammonia solely by the microorganisms. Nature always finds a way.

All that said. I still have a number of heavily planted tanks that I enjoy. When it comes to fish keeping, there is more than one way to skin a cat (just an expression). My fish have all of their skin/scales/scutes. :)
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Re: About filtration

Post by Lycosid »

TwoTankAmin wrote: Tue Mar 31, 2020 5:08 pm I am a huge fan of Mattens. I have 3 tanks which rely primarily on them. Almost as much, I like the Poret foam cubes. This is a brand and I am sure there are other brands as good, I just ended up using this one.
I'll second this. I have a whole aquatics lab running off Mattenfilters, and we never have water quality issues.
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Re: About filtration

Post by Boris »

TwoTankAmin wrote: Tue Mar 31, 2020 5:08 pm Big foam filter media will tend to do a fair amount of denitrification and still not result in water which is short on oxygen. I do not need to do all sorts of complicated testing to know this. I use these filters in tanks where I keep Hypancistrus species breeding and growing out. I have a lot of Xingu river fish and they live in water temps from the low 80s F to bouts of time at 90F+. This water temp tends to hold less oxygen than cooler water. But the fish have a need for high oxygen levels. My plecos do not die very often, do grow nicely and do reproduce successfully, QED the water must be OK in terms of oxygen levels being adequate and nitrogen levels being almost absent (i.e. not testable without expensive lab equipment).
Hello again!
I am slowly learning and getting to grips with the topic and at the moment I have three tanks recently set up with different approaches.

In the first sentence quoted above, do you mean nitrification instead of denitrification?
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Re: About filtration

Post by TwoTankAmin »

No, I meant denitrification. There are a type of bacteria called facultative anaerobes (or aerobes). These are able to function using oxygen or, when oxygen is depleted, use an alternative. For some this is nitrate. When they use nitrate the end product is nitrogen gas which returns to the atmosphere.

Because there is such a massive volume in a mattenfilter for the bacteria to form the bio-films in which they live, over time a great variety of microorganisms will colonize the foam. The result is there will be some pathways through the foam where the aerobic organisms will use all of the oxygen in the water following that pathway through the media. What there will be instead is the nitrate produce by the Nitrospira (nitrite oxidizers). When this occurs the facultative bacteria will switch from using O to NO2. The result is this nitrate never makes it back into the water column, it is broken down.

Every nitrifying bio-film will have some small parts that do the same thing, even when not using massive media. However, in such cases the amount of denitrification in the average filter is not significant and we do not even know it is occurring as our nitrates will still build up.
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Re: About filtration

Post by Boris »

Thanks!
That is what I was thinking.
My plans for a Synodontis tank were put on hold due to the recent restrictions on movement so in the meantime I got a group of C. moorii for the 100 gallon.
I also installed a matten filter but since the tank was up and running I didn't want to empty it to install a corner filter I opted for a full width version. This is 50x50 cm and I was afraid 2" would be too flimsy so I doubled up and have 4" of 10 ppi across one end.
I have seven medium size fish and feed what they will eat once a day. If it is frozen mysis it is 2 cubes, if that means anything.
My impression is that the nitrates are increasing much slower than I expected and, checking the numbers now when I write this, they seem to be slowing even more as time passes. At the end of last month I had 10 ppm, did a 50% water change. A few days later I measured 3 ppm and am now at 5 ppm.
I concluded that there must be some denitrification going on somewhere but that would mean water with 6 mg/l oxygen going in and somewhere within those 4" reaching 0,2 mg/l which sounds incredible but I haven't got a clue to how much ammonia can be converted with 1 mg oxygen.
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Re: About filtration

Post by dw1305 »

Hi all,
Boris wrote: Wed Jul 29, 2020 8:25 pm .......but I haven't got a clue to how much ammonia can be converted with 1 mg oxygen.
As molar values it is NH4+ + 2O2 and as mass its 1.00 NH4 + 3.56 O2.
Boris wrote: Wed Jul 29, 2020 8:25 pm I had 10 ppm, did a 50% water change. A few days later I measured 3 ppm and am now at 5 ppm.
I'm a bit wary of nitrate test kits. Because all nitrate compounds are soluble you have to reduce nitrate (NO3-) to nitrite (NO2-) before you can form an insoluble coloured compound. There also some issues with Ion Selective Electrodes, mainly interference from other monovalent anions.

cheers Darrel
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Re: About filtration

Post by Boris »

mg/l is mass but what is ppm, is it mass, volume or molar?

Yes, I know you have cautioned about hobbyist test kits but they do give a trend which follows prediction. After a water change they show a steady increase until the next WC and when you start up a new tank you get the increase-decrease curves on NH, NO2 and NO3 so i think they are useful for the purpose?
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Re: About filtration

Post by Bas Pels »

As ppm stands for parts per million, one would assume it refers to a molar - 1 micromol of something per mole of something else.

The reality is different, ppm is most often read, by aquarists, as mg per liter. A millionth of the mass

I got to admit, it is rather distracting, after all, a liter of water is 55.52 mol of water. Adding to that 135,5 mg of cupper (II) chloride, that is 1 millimole, would give 1/55,52 or 0,01801 ppm, particle based

But in mass, it is 65 mg of cupper ions in 1 liter. Thus 65 mg/l or 65 ppm mass based

Personally, graduated in chemistry, I never use ppm, as it is quite confusing.
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Re: About filtration

Post by TwoTankAmin »

I was pretty much taught what Darrel said about nitrate testing. I was also taught that the nitrate kit is most inaccurate in the 0 - 20 ppm range.

Think about how many routes water can take through a matten set-up. Then consider the fact that the bio-film does not form uniformly inside all that foam. The result is in one place there is lots of O left in some of the water exiting the matten and in another place it follows a pathway where the O gets used up before it can exit. Because the facultative bacteria can switch between oxygen and nitrate, where inside the foam denitrification occurs can change.

I was also taught that one of the things that occurs inside a matten is it will deal with a lot of the waste that has the potential to cloud the water and/or to break down into ammonia. Some of the organisms inside the matten consume organic waste before it can become ammonia which needs to be handled via a different process. This, of course, does not result in nitrate.

it is one thing to talk about the world of microorganisms, it is another actually to wrap one's mind around a totally invisible universe of these things inside our tanks. However, "the proof is in the pudding." When we see our water is always clear and nitrate etc. appears to be lower and the fish are healthy and even spawning and the offspring are thriving, something good must be happening.
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Re: About filtration

Post by Boris »

This thread has links to threads with links so I am not sure where I read it but somewhere, I think it was Darrel, mentioned "offgassing through a plenum"?
There are no results when I search this forum for either plenum nor Novak but are you familiar with Dr. Kevin Novak?
He advocates having a plenum (gap) between the substrate and the bottom glass. The aim is to eliminate anaerobic areas and to avoid the sulfate reducing bacteria.
It can also promote the facultative anaerobes and denitrification to nitrogen gas which I think was meant in the quote above?
I have used the under gravel filter I had to create such a plenum under 2" of fine sand in the 100 G.The lift tube from the UGF is led through the matten filter so the slight low pressure created by the MF works toward a very slow downward movement through the sand.

What are your thoughts on this?
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Re: About filtration

Post by dw1305 »

Hi all,
Boris wrote: Thu Jul 30, 2020 4:45 pmThere are no results when I search this forum for either plenum nor Novak but are you familiar with Dr. Kevin Novak? What are your thoughts on this?
I am, my thoughts are that he doesn't understand why his "UKAPS: biocenosis buckets are successful, or how they work.". Unfortunately he has removed a lot of the posts, picture and videos from his blog. I was interested in talking to him, but he was less interested in talking to me.
TwoTankAmin wrote: Thu Jul 30, 2020 4:41 pm.....I think about how many routes water can take through a matten set-up. Then consider the fact that the bio-film does not form uniformly inside all that foam. The result is in one place there is lots of O2 left in some of the water exiting the matten and in another place it follows a pathway where the O2 gets used up before it can exit. Because the facultative bacteria can switch between oxygen and nitrate, where inside the foam denitrification occurs can change.........
it is one thing to talk about the world of microorganisms, it is another actually to wrap one's mind around a totally invisible universe of these things inside our tanks. However, "the proof is in the pudding." When we see our water is always clear and nitrate etc. appears to be lower and the fish are healthy and even spawning and the offspring are thriving, something good must be happening.
My guess is that is what is happening.

It is worth listening to Stephan Tanner, who is <"linked in earlier in the thread">.

Also have a look at <"Deep gravel....."> (also linked in earlier). It is quite a long thread but it will repay reading.

cheers Darrel
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Re: About filtration

Post by Boris »

TwoTankAmin wrote: Thu Jul 30, 2020 4:41 pm I was pretty much taught what Darrel said about nitrate testing. I was also taught that the nitrate kit is most inaccurate in the 0 - 20 ppm range.

I was also taught that one of the things that occurs inside a matten is it will deal with a lot of the waste that has the potential to cloud the water and/or to break down into ammonia. Some of the organisms inside the matten consume organic waste before it can become ammonia which needs to be handled via a different process. This, of course, does not result in nitrate.

However, "the proof is in the pudding." When we see our water is always clear and nitrate etc. appears to be lower and the fish are healthy and even spawning and the offspring are thriving, something good must be happening.
I am going through the "deep gravel" thread and there is so much information to digest and also some points I would like to clarify but we will have to take them bit by bit so as not to be confused.

@TwoTankAmin I am not calling you out specifically by quoting your post. It just had the right context.

I have to disagree on the nitrate tests. There is very seldom an "off" measurement or random fluctuations. If you take a measurement every other day you don't get: 3 5 10 5 15 10.. but rather a consistent 3 3 5 5 10 10 15...
Despite the inherent uncertainty they seem to work for what we use them for.

We are taught many things but have you also experienced them to be true?
I am experiencing an apparent lack of nitrates associated with my matten filter so now I can start calling it knowledge? I find that, especially with filtration, there is often very little real data behind various statements.

Something good must be happening and that is fine for this tank but in order to replicate it on future tanks I need to know exactly what is going on?

Regarding the plenum, I have divided nitrification and denitrification between the MF and the substrate. If I have well oxygenated water, do you see this as functional or does it have an inherent problem? One point could be that the substrate can not be siphoned so all waste must be processed in tank increasing BOD?
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