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Here's a good question sent to me today.

Question: I read your article on nitrogen uptake in aquatic plants. (Note: article is available on my website.) Given that (most) aquatic plants are adept at processing ammonium (ammonia?) and nitrites. Can I conclude that we can over-filter our water with biological filtration? In other words, are we filtering out the very chemicals that plants need? Thank you again.

Answer: Yes. Filtration removes ammonia that plants prefer and replaces them with nitrates, which require more energy for plants to fulfill their nitrogen needs. Moreover, filtration sometimes includes lots of aeration/bubbling which degasses off precious CO2.

Ammonia is taken up by plants more easily than ammonium; in fact, ammonia diffuses freely into the plant. Ammonia (NH3) has no electrical charge, so it easily crosses the lipid membrane barrier of plant cells. Ammonium (NH4+), in contrast, has a positive charge so cells can regulate its uptake-which is a good thing--but that requires some processing. I would conclude from this that ammonia is probably taken up slightly more easily than ammonium by plants.

There's a Golden Rule here: the uncharged nature of ammonia is part of the reason why it is toxic to plants and fish when it is in excess. Their cells simply cannot regulate its uptake. It diffuses unregulated through the lipid membrane barrier and creates havoc within the cell. The same rule applies to H2S; because it has no charge, cells cannot keep it out.

Moderate water circulation can be useful. It brings nutrients to plant leaves more quickly. It also distributes heat, especially beneficial to large, deep tanks. Organic soil substrates like potting soil are oxygen-hungry first 8 weeks, sometimes making life difficult for plant roots. Circulation of the overlying water helps aerate those soil substrates.

If you have a small tank (1-10 gal) with good submerged plant growth and a moderate fish load, you don't filtration. With a larger tank newly set up with soil and with lots of fish, you might need some filtration to help oxygenate water as well as to remove ammonia.
 

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I use an aqualcear 50 on my 55g NPT with great success. I think some water movement is vital, I just added a powerhead. THe fish love it, we shall see about the plants.
 

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I use Aquaclear filters on most of my tanks, but only with mechanical media--the sponge that comes with the filters. Some biological filtration does occur in the sponge. I'm careful to keep the water level high enough in the tanks so that the output from the filter flows smoothly with no splashing or free fall into the tank.
 

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I use Aquaclear filters on most of my tanks, but only with mechanical media--the sponge that comes with the filters. Some biological filtration does occur in the sponge. I'm careful to keep the water level high enough in the tanks so that the output from the filter flows smoothly with no splashing or free fall into the tank.
I'm going to set up a 17 gallon soon. Would this qualify as a tank benefiting from a HOB for circulation? Also, do you pull out the carbon filter that comes with an aquaclear and just leave the foam?
 

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Filter carbon is only effective for a short time. It soon gets loaded with large molecules and, from then on, it only acts as a biofilter - a place for bacteria to establish colonies. If you remove it before using it, you can save it for the possibility of later wanting to remove medicines or organic dyes from the water.
 

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I had a silly question but I'm currently adding more fish to my 4 week old 75 gallon planted aquarium. If ammonia is the first thing used by the plants for energy then why have a moderate fish load? Wouldn't more fish make more ammonia? I have 5 nickle sized angelfish, six panda corydora, 1 betta, and I just bought 8 red neon blue eyed rainbow online. I eventually want to add 14 or 15 cardinal tetras and some German Blue rams would that be considered a moderate fish load for a 75 gallon or is that excessive? Thank you for the input in advance.
 

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I'm going to set up a 17 gallon soon. Would this qualify as a tank benefiting from a HOB for circulation? Also, do you pull out the carbon filter that comes with an aquaclear and just leave the foam?
Yes, don't install the carbon packet. And you don't need the bag of ceramic biomedia that comes with the filter either.
 

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I had a silly question but I'm currently adding more fish to my 4 week old 75 gallon planted aquarium. If ammonia is the first thing used by the plants for energy then why have a moderate fish load? Wouldn't more fish make more ammonia? I have 5 nickle sized angelfish, six panda corydora, 1 betta, and I just bought 8 red neon blue eyed rainbow online. I eventually want to add 14 or 15 cardinal tetras and some German Blue rams would that be considered a moderate fish load for a 75 gallon or is that excessive? Thank you for the input in advance.
Plants don't use ammonia for energy, they use it for a nitrogen source. And too much ammonia is toxic to both plants and fish.

As far as your fish list goes, my main concern is that those angelfish will not stay nickle size for long!
 

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Ok so moderate amount of ammonia good too much is bad...got it 😉

As far as the angelfish go I understand they will grow hand sized in some cases and was planning on them being the stars of the show. I was just trying to determine the moderate fish load thing. Moderate is a subjective thing I suppose. With that being said as my tank sits: 1 betta, 5 angels, 6 coryforas, 8 pseudomugil luminatus. In you guys opinion is there any room for a future school of 12 to 15 Cardinal tetras, 10 nerite snails, and a couple of rams or will this be too much for my heavily planted dirted tank?
 

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You may not have too many fish, but the combination may not work. Full grown angelfish will eat cardinal tetras, and will probably terrify the blue eyes and rams so much that you will never see them.
 

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I have had also success with smaller no filter and no water circulation tanks.
I am less worried about NH4 or NH3 in my situation, plants and soil work very well for me.
What I am sometimes a bit unsure how much is the risk for low oxygen levels without water circulation. I think I have seen issues if there is alot of duckweed growing on the surface. I would not call my tanks heavily stocked by any means. In my case water temperature is also lower, around 21C stable even in the summer.

What is the recommendation on filter and water circulation with shrimp or snail only tanks?

I am experiencing with HC Cuba monoculture and RCS shrimp in a 35 liter NPT with no filter nor water circulation and things have worked fine since day 1 (6 months ago).

1585852889777.jpg
 

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I have had also success with smaller no filter and no water circulation tanks.
I am less worried about NH4 or NH3 in my situation, plants and soil work very well for me.
What I am sometimes a bit unsure how much is the risk for low oxygen levels without water circulation. I think I have seen issues if there is alot of duckweed growing on the surface. I would not call my tanks heavily stocked by any means. In my case water temperature is also lower, around 21C stable even in the summer.

What is the recommendation on filter and water circulation with shrimp or snail only tanks?

I am experiencing with HC Cuba monoculture and RCS shrimp in a 35 liter NPT with no filter nor water circulation and things have worked fine since day 1 (6 months ago).

View attachment 63153
There is going to be an article about oxygen levels in primarily no-tech tanks released in an online Czech magazine in the coming weeks, I will ask the author if I could share his measurements here sooner (including some "standard" and high tech tanks). Results are quite interesting (I have access to the preliminary version with raw data/notes). In the "worst" case I'll translate the final version of the article once it's made public.
 

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There is going to be an article about oxygen levels in primarily no-tech tanks released in an online Czech magazine in the coming weeks, I will ask the author if I could share his measurements here sooner (including some "standard" and high tech tanks). Results are quite interesting (I have access to the preliminary version with raw data/notes). In the "worst" case I'll translate the final version of the article once it's made public.
This is great. I'd love to see some results with established NPTs, so not regular low tech tanks without soil substrate. That's a different setup.
I am usually not that worried about oxygen levels without circulation in my smaller NPTs as long as there is not too much duckweed on the surface, amount of fish is reasonable and water temperature is not too high (say around 20-24C).
However, it would be nice to see where are the "limits", how much room for error is left to stay on the safe side without water circulation.

In fish stores with very crowded tanks, if the filter stops (often its a sponge filter with air bubbles) fish may gasp for air in 15-25 mins...
 

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The only time I've had oxygen level problems in my Walstad tanks is during power failures. With both circulation AND lighting shut off, fish in my somewhat crowded tank show distress in about 48 hours.
 

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This is great. I'd love to see some results with established NPTs, so not regular low tech tanks without soil substrate. That's a different setup.
I am usually not that worried about oxygen levels without circulation in my smaller NPTs as long as there is not too much duckweed on the surface, amount of fish is reasonable and water temperature is not too high (say around 20-24C).
However, it would be nice to see where are the "limits", how much room for error is left to stay on the safe side without water circulation.

In fish stores with very crowded tanks, if the filter stops (often its a sponge filter with air bubbles) fish may gasp for air in 15-25 mins...
Unfortunatelly I can't say anything in details now (author asked me to wait), but..this is my summary which might help a little.

Generally speaking (and this is nothing new), tanks with no circulation tend to have very big variation of DO levels between night and day, tanks with filters (especial air driven sponge ones) usually have quite stable parameters.

It's impossible to tell oxygen levels by just looking at the tank, only very high oversaturation is visible (pearling). Hypoxia has different impact on livestock - some fish are able to live and breed for years even when DO is less than 2mg/l during night. Per several studies, long term or regular hypoxia has detrimental effect on fish (deformities, sickness, stunted growth etc.), but it depends on the species and their natural habitat and physiology.

If you're worried about DO levels, you can basically do two things:
1. increase amount of plants, increase the lightning period (14-15 hours) or increase the light intensity
2. add an air driven filter/air stone (mainly during night when no photosynthesis occurs)

More to come at the end of April.. :)
 

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Discussion Starter · #19 ·
I am experiencing with HC Cuba monoculture and RCS shrimp in a 35 liter NPT with no filter nor water circulation and things have worked fine since day 1 (6 months ago).

View attachment 63153
Nice tank! AND it shows that one can grow HC Cuba in an NPT when this species doesn't have to compete with other species.

Good to remove excess duckweed, as it will block oxygen diffusion from the water surface.

BTW, I've found that an ordinary kitchen fork works great for removing excess duckweed.
 

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I am hanging couple shrimp bowls by the window with heavy floating and carpet plants and zero tech, meaning no circulation, filter or heater. At first I worried about floating plants blocking air exchange so I placed an air tube ring to keep a breathing hole open. I later removed the ring and didn't see any difference. I have no measurement of O2 but observed pearling during 4 to 6 hour sunlight period and bright shade for the balance of day. I measured huge fluctuation of pH though, from 7.2 before to 8.5 during sunlight period, and huge diurnal temp change of as much as 20 F. My shrimp and snails are thriving and never show stress, so they must be adequately oxygenated and not bothered by huge temp and pH fluctuations. Inverts have low bio demand and since I have no fish, I don't know how fish will fair under the same set up.
 

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