Myth Or Fact

[fry_lover]

Three things;

1. You can (in theory) have a Fresh Water aquarium with fish and plants and NO filtration at all (and it works!) Just a densely planted tank, where the plants do all the "work" a filter would do.

I could have sworn i read about that somewhere, a while ago, i guess the tank would have to be completely lush with plants like one of those Dutch or German set-up's you see on the internet. If this is possible in theory, would you have to have a real low stocking level of fish then? Again, if this holds up in theory, would you need a pump of some kind anyway for water movement (as wouldn't the water go stagnant at the top if it's completely still?)


2. If you use plant fertiliser you reduce the plants efficiency levels in removing Nitrate? And possibly Ammonia?

Again, nagging at the back of my mind, i heard something about plants getting "lazy" when given fertilisers and that they consume the fertilisers before the natural "fuel" in the tank, like ammonia and nitrate. But then again, if the fertilisers helps the plants grow, would they not be able to consume more nitrate anyway as they are healthy and growing? If i used no fertilisers, would my plants be extra hungry for the nitrate in my tank? This seems a "catch 22" as if i did stop the fertilisers then i might risk the plants health which would then defeat the whole purpose


3. Assuming lighting levels are correct, the "average" reasonably easy to grow and hardy plants do not need any fertilisers of any kind as they will get all the "stuff" they need from the waste of the fish

assuming the tank is stocked reasonably well? I say "stuff" and not nutrients as obviously there are nutrients in plant food that are unlikely ever to be produced by fish.

Not really considering any of this stuff, just interested in the science behind it.

Thanks

 

[fry_lover]

Just been reading some of the Pinned Plant Threads, amazing amount of info on there and i will go back to them, especially interesting is that for 2 wpg lighting (or less) and no CO2 you generally dont need to use fertiliser (or dont have to) cant remember the exact wording.

Be interested in claryfying the above though as "myth or fact", i think number 3 is Fact (under certain circumstances)

 

[wei0204]

I am interested to know how true it is too for the above 3 "questions".

 

[George Farmer]

1. You can (in theory) have a Fresh Water aquarium with fish and plants and NO filtration at all (and it works!) Just a densely planted tank, where the plants do all the "work" a filter would do.

Yes. Some water circulation is recommended though to prevent the water from going stagnant, to give better oxygen exchange at the surface, and to transport the nutrients. Low fish load and heavy planting are essential. Diana Walstad runs tanks with no regular filter, just a small powerhead for circulation.

2. If you use plant fertiliser you reduce the plants efficiency levels in removing Nitrate? And possibly Ammonia?

Basically no. If any one nutrient goes deficient then it will affect the plants ability at uptaking things like NO3 and NH3/4. However the use of fertilisers depends on the set up, that leads us to your next point....

3. Assuming lighting levels are correct, the "average" reasonably easy to grow and hardy plants do not need any fertilisers of any kind as they will get all the "stuff" they need from the waste of the fish

Basically yes. Low-moderate light with undemanding plants and you may be able to supply sufficient nutrients through fish food/waste and water changes. A nutrient-rich substrate would also be an important aspect if using this technique.

If you are interested in these low-tech techniques then Diana Walstad's book is very good - http/www.amazon.co.uk/gp/search/ref=pd_l...p;index=blended

Also try googling "low-tech planted" for more info.

 

[nry]

De-ja vu

 

[spankone]

not sure where i saw it but there is a website where a guy has down a planted tank, thats basicly works like a proper eco system

 

[nry]

It's also what people had before filters were commonly used. My Dad had a coldwater tank for years without a filter, can't recall any fish dieing.

 

[fry_lover]

LOL Nry

every now and then when i need the technical advice i use both forums!!! You cant beat this forum for sheer technical knowledge look at the amount of posts some of these peeps have!!! Great and quick advice on here mate.

Thanks George, i will take a look at the book mentioned.

 

[nry]

It is pretty good

 

[JamesC]

2. If you use plant fertiliser you reduce the plants efficiency levels in removing Nitrate? And possibly Ammonia?

Basically no. If any one nutrient goes deficient then it will affect the plants ability at uptaking things like NO3 and NH3/4. However the use of fertilisers depends on the set up, that leads us to your next point....

I think I have agree with the question if we are talking about adding nitrates as the fertiliser. Plants will always opt for the most energy efficient way of acquiring nitrogen. The easiest is ammonia followed by nitrite, followed lastly by nitrate. So if all 3 are in the water at the same time ammonia will be used first. Now nitrate in our tanks come in two forms, organic and inorganic. Organic nitrate comes from fish poop and inorganic comes from the potassium nitrate we add. Plants find it easier to strip nitrogen from inorganic nitrate than they do organic nitrate. So to answer the first part of the question, yes adding inorganic nitrate will reduce the plants efficiency at removing nitrate produced by the fish as the plants will go for the easier option.

James