Just An Update

[Syphoniera]

Hi, Loraxchick,
darn tootin' this certainly is a wonderful forum, with so many great and helpful people and so much knowledge.
What a relief to find it, especially with such a nice, big Betta forum.
Honestly, though, I must sleep someday; I did read your description given and obviously unconsciously (literally) remembered...
It's so cool that for virtually every type of aquarium method, there's an identifiable name and a following, info on whatever direction you're going.
The Walstad is based actually on minimal interference; soil-based, gravel-capped, a wide variety of plants initially added to see what does well in each tank, sunlight where possible and additional light typically below 5 watts per gallon and often much lower, low dosing, although potassium (and, if a source wasn't added to the soil, calcium and magnesium) often need(s) to be regularly added, and/or a bit of Flourish and Excel, or their equivalents are used by some, at least in the early days.
The idea is that a balance is found and supported, so far as possible, with relatively high feeding and plenty of small snails to not only eat algae but to convert any excess fish-food to plant food.
The method typically produces soft, acidic water much appreciated by Bettas, Tetras and others, and plants tend to grow well but not overly fast, depending on lighting levels.
Diana Walstad now recommends some degree of water movement and mechanical filtration, although many people have had success, especially in smaller tanks, with no filtration at all.
Water changes can be reduced over time as the tank matures to the point where some people do changes in some tanks only a few times a year, with weekly top-ups, pruning and whatever general maintance is required.
I'm not sure how good my description is, but you might be interested, if the pruning's getting to you.
Your set-up sounds closer to Tom Barr's, (apart perhaps from the dosing regime? His is pretty specific, I believe, all worked out through ceaseless experimentation. He has an interesting and highly successful method for those devoted to the CO2 thing, although I'm not much up on it, as I'm going in a somewhat different - and very low-tech - direction) where the plants are an integral part of the system but growth is artificially stimulated beyond that which would normally occur.
That's kind of one of the dividing lines in the rather inchoate definition of El Natural people keep attempting to solidify.
But of course there are endless combinations as different people work toward the style that suits them best.
If you have an excess of plants, perhaps your LFS would give you credit in trade?
I can never stand throwing away (murdering) healthy plants, so if I'm only allowed to set up a limited number of tanks for which I'll need cuttings (two empty and waiting and one - with a Betta waiting for his upgrade from 10 to 15 gallons - to redo as a Walstead which has its own plants already and a couple of the others to be re-done down the road) I might try that myself.
I think it'd just be so much better if I started a new tank every time I collected enough cuttings, lol.
(Of course, I'm still doing water changes about 6 days of the week at this point, one larger or several smaller tanks almost every day; it'll be different once I'm sure various of the tanks are OK with gradually decreasing these.
Right now it's rotational, with a few little ones needing twice-weekly right now, so easy to keep straight by just going around the circle, apart from specific days, until I'm back where I started.)
Who needs a life - I have fish!

 

[loraxchick]

Wow. I cant wait to read up on all this fun stuff over the next few days. The bit about the snails was particularly interesting. The plants i bought were not "snail free". I started out with about three and, well, you know how that goes. Initially i said, hmmmm. we'll have to see you they effect the chemistry. i was worried (slightly), even after cycling, that the snail population would cause a spike in nutrients that i the plants wouldnt be able to handle so i kept a close eye and held my breath. But i honestly liked the snails for several reasons (i could never think of them as "pests").
1)the Bettas love to watch them
2)they keep the plants so very clean!
as far as the population goes at the moment, i have three-ish larger ones and so very many teeny tiny smails that never seem to grow up. i figure food availibility will naturally cull the population and the carbonates from their shells will be recycled. Exactly what i feel is happening. Our Kh is pretty steady even with loads of new snails all the time.
I also found it interesting about the non-injection co2 method. I have neve rtried it but have certainly given that some thought, but wanted to let the plants settle in and see how they handle this system. And it is a small-ish system- a 6gal. perhaps ill do my homework and try that soon. but my little fishies are so happy id hate to upset the balance in there. But i also think the work would be worth it. Im all about natural- i have a BA in Biology/ marine ecology. That is what drove me in the past to do the whole planted tank as a filter in the past with fantastic results in a 20 gal. Figured id give it a go with the boys (been a while since the last time) I just never gave the methods a thought, to me it makes sense. why try to fool nature, let nature take care of itself!
and a quick note about the plants. I have certainly given thought to trying to sell some for store credit. I have limited options that are nearby, really just Petsmart. I dont know how receptive a big chain would be to an "independent supplier", esp. since the quantity is not overly large at the time of pruning. That would be nice, though, to get some store credit with a turtle who eats like a piggy, my betta boys, a big droopy dog to feed and spoil as well as a few fish in with the turtle who clean up her mess. So that is worth looking into maybe ill have to get a tank just for plants!
I can not say thank you enough for giving me a new homework assignment and reading up on the methods you have stated. Will be a fun way to pass the time!

 

[Syphoniera]

Hi, Loraxchick,
don't know if you'll check back here or not, but just came across a thread started by Tom Barr somewhere in the 'related links' - shouldn't surprise me as he does tend to pop up, either personally or in mention, hither and yon.
But, boy, I love this forum - a little bit of everything somewhere...

'... i have a BA in Biology/ marine ecology. ...' What a cool and very handy thing to have your degree in. I see your interests/priorities have been properly set for a very long time, lol.

The snails are actually an essential part of the Walstad system, and contribute not only through fertilizer-producing break-down of waste but through the very nutrients they respire, in supporting plant growth while cleaning.
Even in your somewhat different system, if you'd eliminated the 'pest' snails, I suspect algae problems would have manifested.
And, as you point out, if sufficient minerals of the more lasting type are present, nothing much is really lost by this as various things are ultimately recycled if their shells remain.
Such plant-based low maintenance methods are great for those of a conservationist bent, besides ultimately saving a small fortune in water bills for those with severe Multiple Tank Syndrome or large tanks of the sort (sniff, sob) I can't have.
Your idea about a separate plant tank for cuttings sounds well worth while: I hauled out and set up a little tank just to grow cuttings out in for future use - although it somehow turned into a cherry shrimp mini farm... (rubs hands briskly together and cackles, 'And the next one may mysteriously sprout another Betta...')
Only in emergencies, of course.
You'll probably be one of those people whose cuttings actually covers the cost of fish food, meds and fertilizer - and maybe someday you could expand into the escargot industry.
And so a dynasty is born...

 

[Syphoniera]

Because I wasn't looking for it, I came across one of the articles, where plants preferencially take up ammonia.
And because it's so important, a great deal is quoted below, although things like tables and references have been left off.

This explains why a well-planted tank doesn't require cycling in the same manner as one with no or few plants, in order to provide a healthy environment for the fish within.
And I hope this reassures some of the people concerned about potential fish suffering under these circumstances.

http/www.aquabotanic.com/plants_and_biol..._filtration.htm

PLANTS and BIOLOGICAL FILTRATION

by Diana Walstad


Plants are much more than tank decorations; they help keep the fish healthy. Nitrogenous compounds, particularly ammonia and nitrite, are extremely toxic to fish. Hobbyists have for many years relied heavily on the bacterial process of nitrification (i.e., ‘biological filtration’) to convert these toxic compounds into non-toxic nitrates. Hobbyists and even retailer of aquatic plants too easily ignore nitrogen uptake by aquarium plants or assume (incorrectly) that aquarium plants mainly take up nitrates.


Aquatic Plants Prefer Ammonium Over Nitrates


Many terrestrial plants like peas and tomatoes do grow better with nitrates than ammonium [Ref 5]. Thus, some botanists assumed that aquatic plants would similarly take up and grow better with nitrates. However, actual experimental studies suggest otherwise.

Scientists from all over the world have studied nitrogen uptake in aquatic plants under a variety of experimental conditions. I was able to locate published studies on 33 different aquatic plant species. Only 4 of the 33 species preferred nitrates (Table 1).


Table 1. Nitrogen Preference of Tested Species. Full references for these studies are listed elsewhere [10]


Even then, these 4 species come from unusually nutrient-deprived environments that are not typical for aquarium plants. Moreover, the extent of the ammonium preference is monumental. For example, the duckweed Lemna gibba removed 50% of the ammonium in a nutrient solution within 5 hours, even though the solution contained over a hundred times more nitrates than ammonium [8]. Elodea nuttallii, placed in a mixture of ammonium and nitrates, removed 75% of the ammonium within 16 hours while leaving the nitrates virtually untouched (Fig 1). Only when the ammonium was gone, did it seriously take up nitrates. Likewise, when the giant duckweed Spirodela oligorrhiza was grown in media containing a mixture of ammonium and nitrate, the ammonium was rapidly taken up whereas the nitrates were virtually ignored (Fig 2). Because the plants for this particular study were grown under sterile conditions, the ammonium removal could not have been due to nitrification. Also, the investigator showed that plants grew rapidly during the study confirming that the ammonium uptake was not an experimental artifact, but that it probably accompanied the increased plant biomass and need for nitrogen. (The N concentration in aquatic plants ranges from 0.6 to 4.3% of the their dry weight [ Ref 3].

Table 2 shows how fast nitrate and ammonium is removed from the water by the water lettuce (Pistia stratiotes). Plants placed in nutrient solution containing 0.025 mg/l of nitrate-N required 18 hours to take up the nitrates. However, similar plants placed in nutrient solution containing 0.025 mg/l of ammonium-N required only 3.9 hours to take up the ammonium. When the investigators increased the nitrogen concentration, the difference was even greater. Thus, at 13 mg/l N, plants required 71 hours (almost 3 days) to take up nitrate, but if the N was supplied as ammonium, uptake was still just 4 hours.

Nitrate uptake seems to require more effort for aquatic plants than ammonium. For example, the water lettuce took up nitrates much slower in the dark [Ref 6], while ammonium uptake was the same in the light or the dark. This suggests that nitrate uptake requires more energy than ammonium uptake. Furthermore, nitrate uptake often has to be induced before it can be measured. For example, maximum nitrate uptake in the water lettuce did not occur until after the plants had been acclimated to pure nitrates for 24 hours (any ammonium in the water would have prevented nitrate uptake).



Table 2. Hours Required for Water Lettuce to Take Up Nitrates v. Ammonium [6]. Investigators placed plants in beakers with nutrient solution that contained increasing amounts of N given to plants as either pure nitrates or pure ammonium. Hours required for N removal are based on the assumptions that there is 1 gram of plant dry weight per liter and that the solution is constantly stirred. (Note: ‘mg/l’ = milligrams per liter.)

Ammonium actually inhibits nitrate uptake and assimilation in a variety of organisms such as plants, algae, and fungi [4]. For example, algae doesn't take up nitrates if the ammonium concentration is more than about 0.02 mg/l [ REF 1]. Nitrate uptake by duckweed promptly ceases when ammonium is added to nutrient solutions [9]. The inhibition is typically reversible, because plants will start to take up nitrates a day or two after all ammonium is removed from the water. One could hypothesize that the ammonium inhibition of nitrate uptake may protect the plant from taking up nitrates, which can drain energy from the plant (see ‘Aquatic Plants versus Biological Filtration’ below).



Nitrite Uptake by Plants



Although plants can use nitrite as an N source, the pertinent question for hobbyists is- Do aquatic plants remove the toxic nitrite before the non-toxic nitrate? I could not find enough studies in the scientific literature to state conclusively that they do. However, the chemical reduction of nitrites to ammonium requires less of the plant’s energy than the chemical reduction of nitrates to ammonium. (A plant must convert both nitrites and nitrates to ammonium before it can use them to make its proteins.) Thus, it is not surprising that when Spirodela oligorrhiza was grown in media containing both nitrate and nitrite, it preferred nitrite (Fig. 3).


Aquatic Plants Prefer Leaf Uptake of Ammonium



If aquatic plants preferred to get ammonium by root uptake from the substrate rather than leaf uptake from the water, their ability to remove toxic ammonia from the water and protect our aquarium fish would be questionable. Fortunately for hobbyists, aquatic plants seem to prefer leaf uptake of ammonium as opposed to sediment uptake [10]. For example, in a split-chamber experiment with the marine eelgrass Zostera marina, when ammonium was added to the leaf/stem compartment, root uptake was reduced by 77%. However, when ammonium was added to the root compartment, leaf uptake was not reduced. (In split-chamber experiments, plants are grown with their roots in a sealed bottom compartment and with their stems/leaves in a separate upper compartment.)

Work with other plant species supports the above findings. Apparently, the seagrass Amphibolis antarctica can take up ammonium 5 to 38 faster by the leaves than the roots. And Myriophyllum spicatum planted in fertile sediment grew fine without any ammonium in the water. However, if ammonium was added to the water (0.1 mg/l N), plants took up more N from the water than the sediment.

Several aquatic plants (Juncus bulbosus, Sphagnum flexuosum, Agrostis canina, and Drepanocladus fluitans) were found to take up 71 to 82% of the ammonium from the leaves; their roots took up only a minor amount.

Hobbyists using fertilizer tablets for aquatic plants might want to carefully consider the aquatic plant preference for leaf uptake of ammonium (as opposed to root uptake). In ponds and aquariums, plants should be able to fulfill their N needs from fish-generated ammonium in the water. What’s more; nitrogen added to substrates can be detrimental. Ammonium can be toxic to plant roots. Even nitrates added in substrate fertilizer tablets can create problems. This is because bacteria in the substrate quickly convert nitrates to toxic nitrites [10].



Aquatic Plants versus Biological Filtration



Plants, algae, and all photosynthesizing organisms use the nitrogen from ammonia- not nitrates- to produce their proteins. If the plant takes up nitrate, it must first be converted to ammonium in an energy-requiring process called ‘nitrate reduction’.

Nitrate reduction in plants appears to be the mirror image of the bacterial process of nitrification. Nitrifying bacteria gain the energy they need for their life processes solely from oxidizing ammonium to nitrates; the total energy gain from the two-steps of nitrification is 84 Kcal/mol. The overall reaction for nitrification is:



NH4+ + 2 O2 >> NO3- + H2O + 2 H+



Plants theoretically must expend essentially the same amount of energy (83 Kcal/mol) to convert nitrates back to ammonium in the two-step process of nitrate reduction The overall reaction for nitrate reduction is:



NO3- + H2O + 2 H+ >> NH4+ + 2 O2



The energy required for nitrate reduction is equivalent to 23.4% of the energy obtained from glucose combustion [5]. Thus, if nitrifying bacteria in biological filters convert all available ammonium to nitrates, plants will be forced-- at an energy cost-- to convert all the nitrates back to ammonium. This may explain why several aquatic plants (e.g., water hyacinth, Salivinia molesta, hornwort, and Elodea nuttallii) seem to grow better with ammonium or an ammonium/nitrate mixture than when they are forced to grow with pure nitrates [10]. The nitrogen cycle is often presented incorrectly to hobbyists as nitrifying bacteria converting ammonium to nitrates and then plants taking up nitrates. Actually, it consists of both plants and bacteria competing for ammonium. Only if plants are forced to, will they take up nitrates. Thus, nitrates may accumulate even in planted ponds and aquariums.

Nitrification enhanced by filters is essential for protecting fish from toxic ammonia in aquariums without plants. However, planted aquaria are a whole different ballgame. In fact, plants provide an enormously increased surface area within the aquarium for nitrifying bacteria. Planted areas (as opposed to unplanted areas) in natural habitats (rivers, lakes, etc) have been shown to provide an exponentially increased number of colonization sites for bacteria (11). You can be sure that every leaf and stem surface in an established aquarium is coated with a layer of nitrifying (and other) bacteria.

I have been surprised at how little biological filtration is actually required in my planted aquaria. When I gradually decreased biological filtration by removing the packing media from the canister filters, the fish continued to do well. Finally, years later I took the decisive step and removed the canister and outside filters altogether and just used cheap internal pumps to circulate the water. Fish never missed a beat; the planted tank itself is a filter!

Aquatic plants, then, are much more than ornaments or aquascaping tools. They remove ammonia from the water. Furthermore, they remove it within hours (Fig 1, Table 2). When setting up a planted tank, there is no need to wait 8 weeks to prevent ‘new tank syndrome’. (Nitrifying bacteria require several weeks to establish themselves in new tanks and make biological filtration fully functional.) Thus, I have several times set up a new tank with plants and fish all on the same day.

In summary, there is considerable experimental evidence in the scientific literature showing that aquatic plants vastly prefer ammonium over nitrates as their N source. Even in the presence of abundant nitrates, aquatic plants will be sifting the water 24 hours a day for ammonium. Plants in aquariums also increase ammonium removal by simply increasing colonization sites for nitrifying bacteria. I hope this explains why (in terms of fish health) it is worth the trouble to keep plants in aquariums.



(End of quotes)

 

[loraxchick]

thanks so much...interesting (and makes a whole lotta sense!)...EXCELLENT!