My Macho And Very Manly Betta

[ibbledibble]

well probably the cheapest and easiest is duckweed (lemna minor) also duckweed really loves ammonia.

Nitrogen Removal in the Planted Aquarium
Nitrogenous compounds, particularly ammonia and nitrite, are probably the most common pollutants of aquariums. Both ammonia and nitrite are extremely toxic to fish. Aquarium hobbyists depend on biological filtration to convert these toxic compounds into non-toxic nitrates. However, plants and soil bacteria can also remove nitrogen from aquariums.

Aquatic Plants Prefer Ammonium over Nitrates
All plants can use either ammonia/ammonium, nitrite, or nitrate as their N (nitrogen) source. Based on N-uptake studies in terrestrial plants, many people assumed that aquatic plants, like terrestrial plants, mainly take up nitrates. Actual experimental studies with aquatic plants suggest otherwise.

Scientists from all over the world have studied N uptake in aquatic plants under a variety of experimental conditions. From the published studies, I found 29 species of aquatic plants that preferred ammonia/ammonium to nitrate. Only 4 species were found to prefer nitrates.
Figure 2: Uptake of ammonium and nitrates by Elodea nuttallii. Plants were placed in 1 liter of filtered lake water containing 2 mg/l each of NO3-N and NH4-N. Concentrations of ammonium and nitrates were measured at 4, 8, 16, 32 and 64 h (note the logarithmic scale of time axis in the graph). For each exposure period, 3 tanks with plants and 3 control tanks without plants were used. Control tanks (without plants) showed that there was little loss of either NH4-N or NO3-N due to bacterial processes. Figure from Ozimek [8], Fig 1, p 107 in my book.
Moreover, the extent of this preference is considerable. For example, the aquatic liverwort Jungermannia vulcanicoloa was found to take up ammonium 15 times faster than nitrates [6]. 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 [9].

Elodea nuttallii, placed in an equal mixture of ammonium and nitrates, removed 75% of the ammonium within 16 hours while leaving the nitrates virtually untouched. Only when the ammonium was gone, did the plants begin to take up nitrates.

Likewise, when Ferguson [2] grew the giant duckweed Spirodela oligorrhiza in media containing a mixture of ammonium and nitrate, the ammonium was rapidly taken up whereas the nitrates were not. Because he grew the plants under sterile conditions, he showed that the ammonium removal could not have been due to the bacterial process of nitrification.

Also, Ferguson showed that plants grew rapidly suggesting that the ammonium uptake probably accompanied the normal growth process and increased plant material (the N concentration in aquatic plants ranges from 0.6 to 4.3% of their dry weight [3]).
# Figure 3: Lemna minor is one of the many plant species that prefer ammonium over nitrates. Some familiar species with the same preference: Ceratophyllum demersum
# Eichornia crassipes
# Elodea densa
# Pistia stratiotes
# Salvinia molesta
(Table 3, page 108 in my book: Nitrogen Preference of Various Species).

it will reproduce like crazy and all you have to do is scoop out the excess and throw it away.

 

[Minni3]

So duckweed is good in removing ammonia, but not so much nitrates? Is nitrates a by product of rotting fish food and poo? Is it as harmful as ammonia? Do you think the pet store will let me exchange my pleco for some duck weed?

 

[ibbledibble]

So duckweed is good in removing ammonia, but not so much nitrates? Is nitrates a by product of rotting fish food and poo? Is it as harmful as ammonia? Do you think the pet store will let me exchange my pleco for some duck weed?

Ammonia is produced by rotting fish food (which you shouldn't have so long as you don't overfeed) and fish poo. bacteria in the filter and tank break the ammonia down into nitrIte, which is less toxic than ammonia, then another type of bacteria breaks the nitrIte down into nitrAte which is only toxic in large quantities. regular water changes will reduce nitrAte levels. In un-planted filtered tanks, all the ammonia and nitrIte are broken down into nitrAte (thats why you cycle tanks, to build up the bacteria)

If the ammonia is being used up by the plants, there will be less to be converted to nitrIte and aquatic plants will use ammonia in preference, then nitrIte, then nitrAte if thats all thats available so they remove the most harmful substance first.
heres another quote from that article explaining this

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. Thus, when Ferguson [2] grew the duckweed Spirodela oligorrhiza in media containing both nitrate and nitrite, he showed that it preferred nitrite.
Figure 4: Nitrite (NO2) and nitrate (NO3) uptake by Spirodela oligorrhiza. Plants that had been grown with ammonium as their sole N source were transfered to medium containing both nitrite and nitrate. Plants were grown under sterile conditions. Thus, the above changes in nitrite and nitrate levels could not have been due bacterial processses. With permission of Springer Verlag GmbH (Fig 4, p 23 in my book).

Although you may still get a build up of ammonia/nitrIte/nitrAte it will be less than if you didn't have plants reducing it. and you should be doing regular large water changes anyway which will remove the excess.

Your LFS should give you more than just duckweed in exchange for a pleco, as duckweed is very cheap and sometimes considered a weed because it grows so fast, (although all that really means is you have to keep throwing the excess out)

hope this helps