About filtration

[dw1305]

Hi all,

Yes, I understand that but if the plant didn't release oxygen from the roots, the same ammonia that reached this zone would not be nitrified and could be taken up by the plant at less cost. The plant is "giving" the bacteria the oxygen that it then has to reduce again.

It is really all down to amounts, any available ammonia is going to be taken up by nitrifying micro-organisms and plants and it is never going to accumulate and will always be below 1 ppm. It is different for nitrate, it isn't as energy rich, so can build up to ~30 ppm even in natural situations.

cheers Darrel

[dw1305]

Hi all,

I have Walstads book on its way in the mail but I have not read it. However I have suspicions that she is attributing too much to the plants and too little to microbes.

No I don't think she is. It is always plant/microbe nitrification when you have plants, and since she wrote her book there has been a lot of scientific work that has shown that plant/microbe biofiltration can potentially deal with much larger bioloads (an order of magnitude larger) than "microbe only" filtration. (From th linked paper "Myriophyllum aquaticum Constructed Wetland Effectively Removes Nitrogen in Swine Wastewater")

In this study, a three-stage surface flow CW was constructed in a pilot-scale within monospecies stands of Myriophyllum aquaticum to treat swine wastewater. Steady-state conditions were achieved throughout the 600-day operating period, and a high (98.3%) average ammonia removal efficiency under a N loading rate of 9 kg ha-1 d-1 was observed. To determine whether this high efficiency was associated with the performance of active microbes, the abundance, structure, and interactions of microbial community were compared in the unvegetated and vegetated samples. Real-time quantitative polymerase chain reactions showed the abundances of nitrifying genes (archaeal and bacterial amoA) and denitrifying genes (nirS, nirK, and nosZ) were increased significantly by M. aquaticum in the sediments, and the strongest effects were observed for the archaeal amoA (218-fold) and nirS genes (4620-fold). High-throughput sequencing of microbial 16S rRNA gene amplicons showed that M. aquaticum greatly changed the microbial community, and ammonium oxidizers (Nitrosospira and Nitrososphaera), nitrite-oxidizing bacteria (Nitrospira), and abundant denitrifiers including Rhodoplanes, Bradyrhizobium, and Hyphomicrobium, were enriched significantly in the sediments.

To get around the uncertainty of what goes where researchers have used the differing isotopes of nitrogen to try and find out where fixed nitrogen ends up.

I'm not sure which papers everyone has access to, but "<Plant diversity increases N removal in constructed wetlands when multiple rather than single N processes are considered">says

(3) isotope fractionation in the rhizosphere of Coix lacryma‐jobi was primarily due to microbial denitrification while multistep isotope fractionation was detected for Phragmites australis and Acorus calamus (indicating recycling of N), suggesting that species differed in the way they transformed N; (4) the enhanced N removal at high diversity may be due to mutualistic interactions among species belonging to different functional types. Our findings demonstrated that although plant species richness had negligible effects on individual N‐cycling processes, it enhanced the overall ecosystem functioning (N removal) when these processes were considered collectively.

cheers Darrel

[Lycosid]

I have Walstads book on its way in the mail but I have not read it.
However I have suspicions that she is attributing too much to the plants and too little to microbes.

I have Walstad's book. I thought it was very good.

Disclaimer: I also know Diane Walstad (although not well).
Disclaimer to the disclaimer: this means I also know that she raises a lot of fish (especially fancy guppies, these days) and takes her own advice, sometimes running experiments to verify ideas. So while she could be mistaken about why something works she's promoting ideas that she has made work, and my impression is that she is generally careful and cautious.

[dw1305]

Hi all,

I have Walstad's book. I thought it was very good......... I also know that she raises a lot of fish (especially fancy guppies, these days) and takes her own advice, sometimes running experiments to verify ideas. So while she could be mistaken about why something works she's promoting ideas that she has made work, and my impression is that she is generally careful and cautious.

I think the passage of time has made it even more impressive as a book.

No-one else has attempted to write anything of similar scope, and, while you might not agree with absolutely everything in it, 99% of it is veritable gold-dust.

It is the book I wish I'd written.

I really admire both Diana Walstad and Tim Hovanec for having embraced scientific change and revised their opinion based on more recent research (either their own, or by other scientists).

I started posting about "cycling" based on our findings from working on the phytoremediation of waste-water. It was before I knew about all the novel nitrifyng micro-organisms, but I was pretty sure the linear view of cycling wasn't right.

cheers Darrel

[dw1305]

Hi all,

..........I have posted this before.

Petersen, Nils Risgaard‐, Jensen, Kim, (1997), Nitrification and denitrification in the rhizosphere of the aquatic macrophyte Lobelia dortmanna L., Limnology and Oceanography, 42, doi: 10.4319/lo.1997.42.3.052
https://aslopubs.onlinelibrary.wiley.co ... .42.3.0529

It is an older paper but it is still a good indication of what can occur in a planted substrate.

There is an updated paper on the effects of Lobelia dortmanna on rhizosphere microbial assemblages:
"The effect of Lobelia dortmanna L. on the structure and bacterial activity of the rhizosphere". K Lewicka-Rataj, A Świątecki, D Górniak - Aquatic botany, 2018

I have access if any-one wants a copy? But the key findings were:

• The significant influence of L. dortmanna on microbiological processes in the sediments was confirmed. Clearly the high amount, biomass and metabolic and physiological activity of bacteria in the rhizosphere sediments confirmed the stimulating effect of isoetids on sediment bacteria.

• High redox potential and high bacterial respiration rate in the rhizosphere.

• High DOC concentration results in high bacterial activity in rhizosphere.

• CO2 concentration in rhizosphere depends on the number of active bacteria cells.

cheers Darrel

[Boris]

Thank you all three for the links and info!

I am not claiming to contradict Walstad or anyone else. I am simply going through the process where I learn something, think about it, have an idea and then learn why my idea was not correct.

While waiting for Walstad's book to arrive I have done another experiment:

In a 12 gallon I covered the bottom with 1/2" of soil from my dads garden compost. On top of that at least 2" of sand. I used a 50/50 mix of sand/gravel and made a gradient so there is 1 1/2" at front and 3" at the back.
Small sponge filter, two air stones.
No plants! Add water and measure nitrogen.
Expectation:


I don't know how to display a table here.
Result:
Day: 1 3 5 7 8
NH: 0.2, 0.4, 0, -, 0, 0
NO2: 0.5, 0.4, 0.5, 0.1, -, 0
NO3: 5, 5, 10, -, 0,...1,...

Day nine I added 10 small tetras. Day 17 I added another 20 tetras.
Six weeks in nitrate is constant at 1ppm.

So in 8 days I had not only ammonia and nitrite but also nitrate go to zero.
I assume that the necessary amounts of bacteria were present in the soil as a sort of "instant cycle"?

One caveat is I later learned that the "soil" is actually 100% leaf detritus.

[aquaholic]

I am not going to get into the filtration discussion but if you wish to have a low maintenance tank, apart from low stocking rate, I would utilise automatic water change. If you add an overflow, you can apply slow continous drip 24/7 to diplace tank water out. Adding new water in drips allows you to use low pressure piping (very cheap) and your drainage line could be as small as airline tube. If you are adding 3% or less of tank volume daily, you do not need to worry about removing chlorine or chloramine. You do not need to be cleaning filters. You do not need to worry about temperature fluctuations in winter. The auto water change will reduce your maintenance routine, save time and increase safety margin for livestock whether you have one tank or several hundred tanks.

[Boris]

if you wish to have a low maintenance tank, apart from low stocking rate, I would utilise automatic water change.

Yes, automatic water change is a future plan and apart from reducing maintenance it adds stability which may be an underrated quality in our fish keeping?
The only(?) drawback of this is that it is still a wasteful way. The past years have had reoccurring limits to water sources and consequently water usage around the world and even where I live. Reducing the volume of water needed may become increasingly important.

However a certain amount of water change may be necessary for other reasons than nitrogen.
What other reasons are there for small, but reoccurring water changes?

[Bas Pels]

Apart from nitrogen, it looks like fish, at least some species, produce pheromones, reducing the ability of conspecifics to grow.

From my own experience, a single fish in a tank will grow, whether I change water or not. If there are more in the tank, growth will reduce if I don't change water, even if the amount of fish is the same (thus the amount of non-conspecifics is less in case of more conspecifics)

I did not read about it, anywhere, but there does seem to be something

[TwoTankAmin]

Your tap water contains a number of things. Some might evaporate, some may get taken into the fish, some get used by plants. Your fish produce waste that is not merely ammonia. Over time things that are needed get used up. Carbonates are a good example. Things that are not used up because they are not needed can build up and that may cause harm. Other things will get depleted. So think of water changes as restoring the balance to the water.

Every system is different. In my case weekly large water changes work well because we have our own well, so that is what I do. For others a drip/overflow systems works best. There are many ways to deal with water changes and multiple ways to drain and refill. But the goals is always the same, remove the unwanted and replace the used up.

[aquaholic]

My comment was aimed at reducing tank mainenance as that was the origional quest. If someone strives to water change 20% of a tank once a month, simply set the auto water change amount to replace the same 20% once a month. No net loss in water wastage but a big savings in time, reliability and effort.

There are other ways to conserve water, re-use, rainfall capture, ground water, solar evaporators, etc. As previously mentioned, you can reuse water on non conspecific species to reduce growth hormone limitations but unfortunately fish keeping generally is very wasteful on water. If water is a scarce resource then giving up on keeping fish would be the most environmentally responsible thing to do.

If water conservation is less of a priority, you can use water change to totally replace filtration or allow the filtration to be more of a backup. Many of the houses along rivers in SE Asia use cages to grow fish for food. The fish eat food scraps and the river sweeps and cleans constantly so there is no constraint on growth. I've seen huge 80cm sized fish grown up with tiny 100cm cages.

Also not especially relevant but if your town water supply has occasional and unpredictable bad water issues, the 24/7 auto water change is definitely for you. I've lost half a fish room (80 tanks) doing a manual water change on a bad water day. Implementing auto water change has enabled me to add 2 more fish rooms. I'm still time poor but this is my suggestion for lowering maintenance.

[TwoTankAmin]

I realize this is a somewhat old thread. However, it appears as if some under-the-hood changes caused me to get a notification from PC today that I had been mentioned in three posts. All were old threads. One was here.

It occurred to me in working my way back through this thread that the way I do things is actually a pretty efficient water recycling system. Not only do we have our own well, but our waste water is handled by a septic tank and leach field. This is a massive natural filter system which starts at the surface and allows the waste water discharged from the septic tank to be further cleaned on its way back down into the very water table from which is had been removed.

Water removed from my aquariums goes one of two places. The first is into a toilet which means it goes directly into the septic tank. I am sure a lot of what is in that aquarium waste water is a big buffet for the organisms at work in the septic system. The other place the water goes is out a window and directly into the ground. Unlike the septic tank there is no human waste involved. There are landscaping plants where the water lands, so some of it is fertilizer for them. In the summer I will often carry buckets I have rinsed media in from the house to someplace in the garden or lawn and feed the plants/grass.

One last observation on all this. There is a lot of organic waste involved in the septic system much of which is the sort of stuff removed by mechanical filtration in aquariums. The septic system consumes most of it. I know because we rarely have it pumped out and when we do the guy always tells us very little solid waste was removed. This is what happens in a Mattenfilter. Most of the organic waste is consumed.

[dw1305]

Hi all,

I realize this is a somewhat old thread. However, it appears as if some under-the-hood changes caused me to get a notification from PC today that I had been mentioned in three posts.....................

I had a few as well from old threads. @Jools will know why, but I think they come from a time period when "@mention" feature wasn't working.

One last observation on all this. There is a lot of organic waste involved in the septic system much of which is the sort of stuff removed by mechanical filtration in aquariums. The septic system consumes most of it. I know because we rarely have it pumped out and when we do the guy always tells us very little solid waste was removed. This is what happens in a Mattenfilter. Most of the organic waste is consumed.

It sounds like it is working pretty effectively. You can only get more complete digestion by the Anammox (Anaerobic Ammonium Oxidation) process, or having a mix of anaerobic digestion (which is what you have at the moment) and aerobic digestion, but that is a lot less cost effective.

cheers Darrel

[Jools]

Yeah, the mention feature didn't work, fixed now but there was an "unmanaged" issue of mention alert emails to anyone for the last year to bring us back to normal operation. Apologies for that, but always a pleasure to read posts from both authors herein!

Cheers,

Jools

[snowball]

Interesting thread, I have been running my Corydoras tanks "unfiltered" and have not experienced or noticed any adverse effects. Both have strong circulation via large uplift tubes with strong air-stones and a reasonable amount of plants. The tanks are heavily stocked and do get regular large water changes, but I've not had any problems after heavy feeding or when water changes have been skipped for a week or so.

The only drawback as such would be the higher fine particulate matter in suspension, however this was one of the reasons I specifically avoided any mechanical filtration, as originally I wanted to have a self sustaining population of glass shrimp, as well as filter-feeding inverts such as freshwater mussels and riffle shrimp, all of which are doing well. Also I don't have to worry about any fish fry being trapped in a filter.

[dw1305]

Hi all,

Interesting thread, I have been running my Corydoras tanks "unfiltered" and have not experienced or noticed any adverse effects. Both have strong circulation via large uplift tubes with strong air-stones and a reasonable amount of plants. The tanks are heavily stocked and do get regular large water changes............

For me "water changes", "plants" and "oxygen" are important bits, and everything else is really just shuffling the deck-chairs on the deck of the Titanic.

There are quite a few Corydoras breeders and keepers who use planted tanks, these belong to UK breeder Mark Allison.

The only drawback as such would be the higher fine particulate matter in suspension,

You could try a HMF. The cube lifters sold by (forum sponsor) Swiss Tropicals might suit you?

cheers Darrel

[Viktor Jarikov]

Just to be clear, Darrel, are you saying running a tank as described is asking for trouble sooner or later?

What cycles the nitrogen? Plants and whatever BBs live in the tank on the surfaces?

[Bas Pels]

Generally speaking, in the average filtered tank, around half the nitrogen cycling bacteria are living in the filter, the rest does not.

Therefore, stopping the filter would reduce the cycling capacity to half, but in 8 hours the capacity can be back to what it was.

Can, not will, because in many cichlid tanks filtration is needed to keep the water moving and therefore aerated. But this could be achieved with a few powerheads instead of a filter.

Filtering water does remove litter from the water, but the main thing is it turns NH3 and NO2- into NO3-, which is the least toxic of these.

But, as least toxic does not mean non tocix, water changing, or plantr growth, is essential.

[dw1305]

Hi all,

Just to be clear, Darrel, are you saying running a tank as described is asking for trouble sooner or later?

What cycles the nitrogen? Plants and whatever BBs live in the tank on the surfaces?

Hi Viktor, yes that is it. Personally I would prefer some spare filtration capacity (just for "belt and braces"), but potentially the plant/microbe biofiltration will give you enough nitrification.

If it was me, I'd definitely add an HMF or sponge block. I'm a great fan of large sponges.

As @Bas Pels says nitrification is normally limited by oxygen availability, rather than lack of actual physical space for microbial activity. If you can get enough oxygen into the system you can treat ammonia rich wastes with huge BOD values.

As an example sewage has a BOD value of ~200 mg/L dissolved oxygen and at 20 oC 100% oxygen saturation is only about 12 mg/L, but you can still get aerobic nitrification of sewage if you can add enough extra oxygen.

In phytoremediation in constructed wetlands you usually use a combination of plant/microbe aerobic nitrification and anaerobic microbial denitrification to reduce fixed nitrogen levels.

There are always proviso's. You need the plants in active growth, ideally you want rooted emergent and floating plants with access to atmospheric gas levels etc.

cheers Darrel

[bekateen]

You need the plants in active growth, ideally you want rooted emergent and floating plants with access to atmospheric gas levels etc.

cheers Darrel

After experience with my "toilet flush" tank [the 40-gallon breeder about 1/2 - 2/3 with water and powered by an 800gph pond pump, which contains partially submerged potted Pothos and Crypt plants], and in my efforts to breed my

Microglanis

, I've started experimenting with floating rafts (kinons), clumps of twigs and floating wood planted with aerial live plants, mosses, etc., for nitrogen removal. I first brought this up here: Looking for a new biotope to model? How about a floating litter bank habitat?

My challenges are trivial but significant in that most of my lighting fixtures rest too close to the tank, leaving little space for plants, and my hoods are full glass hoods. I need to buy or build overhanging lamps, rather than the conventional tank lights I use now. I also need to adapt or build alternative tank hoods which only partially cover the tanks, leaving room for emergent plant growth. Both easily fixed; I just have to do it.

Cheers, Eric

[dw1305]

Hi all,

After experience with my "toilet flush" tank [the 40-gallon breeder about 1/2 - 2/3 with water and powered by an 800gph pond pump, which contains partially submerged potted Pothos and Crypt plants]

I think a large tank, only 1/2 filled with water, is the easiest option, but you have the added expense and weight of the spare glass etc.

I first brought this up here: Looking for a new biotope to model? How about a floating litter bank habitat?

I remember that thread, it is an interesting one, and I definitely think you are on to something there.

My challenges are trivial but significant in that most of my lighting fixtures rest too close to the tank, leaving little space for plants, and my hoods are full glass hoods. I need to buy or build overhanging lamps, rather than the conventional tank lights I use now. I also need to adapt or build alternative tank hoods which only partially cover the tanks, leaving room for emergent plant growth. Both easily fixed; I just have to do it.

I've bought loads of LED flood lights etc and dimmers with the intention of building all sort of "better" lighting rigs for the tanks, but mainly I've adapted them for other uses or they still sit in their packaging.

cheers Darrel

[bekateen]

Hi All,

Pothos and Java moss growing on floating wood

I think a large tank, only 1/2 filled with water, is the easiest option, but you have the added expense and weight of the spare glass etc.

In the USA, when Petco has their dollar per gallon sale, even after they recently stopped including 40 gal breeders in this promotion, they charge only 50% of normal price for 40 gal breeders - you're spending about $50 USD for a 40 gallon tank (36"x24" footprint). That's still a bargain and worth the spare glass.

I've bought loads of LED flood lights etc and dimmers with the intention of building all sort of "better" lighting rigs for the tanks, but mainly I've adapted them for other uses or they still sit in their packaging.

I have a few of those too!

The simplest lighting solutions I envision are overhanging lighting, suspended either from the ceiling or the fish tank shelf above the tank in question (which requires more vertical separation between tank shelves), or extension stands attached to the tank stand or extending to the floor (i.e., tall floor lamps).

As for the hood, rather than using a traditional glass hood that runs the length of the tank and has its hinged glass pane also running the length, I imagine a better solution is a custom cut piece of glass or acrylic that is as deep as the tank (front-to-back) and only extends over about 1/3 to 1/2 of the tank length, leaving the remaining span open for the kinon to grow above the tank rim. The partial coverage by glass will reduce evaporative water loss and reduce the losses of jumping fish, but obviously it won't reduce either entirely.

Also, this tank plan requires good aeration from below the kinon (either airstones or powerheads), since so much of the water surface (nearly half) may be covered by kinon and will not contribute as much to air-water surface oxygenation. In one of my two current bumblebee tanks, I use both an airstone and a powerhead with venturi, the powerhead blasting through the upward stream of the airstone to push water current and air bubbles horizontally through the tangle of twigs and roots.

Cheers,
Eric