Duckweed:(
- Thread starter Tener ds
- Start date
But on the bright side your nitrates should be nice and low. How much light does it block out from the bottom of the tank?
Hey,
I agree, it has both positive and negative effects.
Positive - it does take up nitrates. It does cover the top of the tank for more peaco of mond for the Ls and fish
Negative - it can get into filters etc and just grows and grows. i would just once a week scoop out a net full if it bothers you.
cheers jk
PS I have now finally after 2years, ridded all of my duckweed from all 8 tanks. Do miss it though, but leave one half of a leaf behind and it will grow :lol:
I agree, it has both positive and negative effects.
Positive - it does take up nitrates. It does cover the top of the tank for more peaco of mond for the Ls and fish
Negative - it can get into filters etc and just grows and grows. i would just once a week scoop out a net full if it bothers you.
cheers jk
PS I have now finally after 2years, ridded all of my duckweed from all 8 tanks. Do miss it though, but leave one half of a leaf behind and it will grow :lol:
Hi mat, my nitrates always stay around 0.5ppm-10ppm.The light is blocked a bit but
the plants are mostly low light plants and grow well.
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Hi BB,I take out a net full when I do my water changes,3 times a week.
It grows so fast. We went to margate for 4 days a while back, removed
at least 80% of what u can see in the pic.when we got back it coved most
off the tank!
The best bit about it is that I see my 2 plecs more, they come out more when there's loads off duckweed.
yup i am sure they love the cover from above. It does grow quick, but it is a personall choice.
cheers jk
cheers jk
I love my duck weed, some fish do too 
. I keep it low by using a skewer and keeping it horizontal with the water surface, I skim the top and when it have it coralled into a corner I lift up the skewer and it brings up a heap of the weed with it, then I repeat till I have removed as much or a little as needed ..this will help keep light levels ok for other plants..I use the skewer method cos, I keep baby shrimp in the same tank and it gives them a chance of getting away from the action if not using a net to get it out...always get shrimp in a net lol
Again, I LOVE MY DUCKWEED
I also have frogbit, love that too..grows bigger in the pond when the yabbies aren't chomping it lol
. I keep it low by using a skewer and keeping it horizontal with the water surface, I skim the top and when it have it coralled into a corner I lift up the skewer and it brings up a heap of the weed with it, then I repeat till I have removed as much or a little as needed ..this will help keep light levels ok for other plants..I use the skewer method cos, I keep baby shrimp in the same tank and it gives them a chance of getting away from the action if not using a net to get it out...always get shrimp in a net lolAgain, I LOVE MY DUCKWEED
I also have frogbit, love that too..grows bigger in the pond when the yabbies aren't chomping it lol
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by skewer do you mean skewer that like kebabs are made with? I can never actually get frogbit to grow it just dies off but i just got a new t8 light system with a white and blue so it looks really good now. Only down side is i have 1 tiny insy winsy bit of frogt bit lol
Hi all,
Dave, you have loads more nitrate than that if you net your duckweed out 3 times a week, and look how lovely and green it is.
So do I, I always have some in the tanks. Have a look at the "Duckweed index" post from your thread here: <http://www.plecoplanet.com/forum/showthread.php?t=10083&highlight=Duckweed+index>. If you really want to get rid of it you have to follow JK's advice, and then let the Salvinia grow to mop up the nitrogen.
cheers Darrel
Do floating plants reduce the surface area of the water, thus reducing the potential dissolved oxygen levels? I'm not sure if this a stupid question or not :cry:
Hi all,
You do need to go a little bit deeper, and make some attempt to quantify the different factors that reduce, or increase, dissolved oxygen levels.
When plants are actively photosynthesising they produce oxygen from:
carbon dioxide + water + light energy → glucose + oxygen + water
(6 CO2(gas) + 12 H2O(liquid) + photons → C6H12O6(aqueous) + 6 O2(gas) + 6 H2O(liquid).
In floating plants most of this oxygen will be lost to the atmosphere, although some will go into solution.
All plants will also take up NH3, NO2 and NO3, and any NH3 and NO2 that doesn't go into the nitrification (which is an oxygen intensive process) will help maintain dissolved oxygen levels.
The demand for oxygen of the water/fish/tank/microbes/plant system can be described by its Biochemical Oxygen Demand (BOD), but unfortunately we can't easily measure this, although we can estimate it.
As a general rule tanks with plants will maintain higher dissolved oxygen levels and better water quality even when the plants aren't photosynthesising (at night), until the plant biomass significantly reduces both flow and surface area.
Other than photosynthesis the major way that oxygen enters the water column is through diffusion at the gas exchange surfaces. Because diffusion occurs over a gradient, we need a water surface that is as large as possible.
We can make the active gas exchange surface of the tank larger by having a rapid turn-over of water, so that there isn't time for the surface layer to become saturated with oxygen before "new" water replaces it at the surface.
Ideally we would like to make the surface much, much larger, which is what a wet and dry trickle filter does. If we used this type of trickle filter, we could to a large degree ignore all the other variables.
As a rule of thumb, in a tank for rheophilic fish, that doesn't have a trickle filter, you need to make sure that the floating plants/leaves don't cover more than 1/2 the surface area in any tank.
As the BOD increases (larger fish load per tank volume, carnivorous fish with a high protein diet), we need to try and make both flow and gas exchange surface as large as possible, whilst also ideally maintaining a large plant biomass. These competing requirements may mean that some plants need to be in a separate sump, possibly with a reversed lighting regime.
This is covered in more detail in: <http://plecoplanet.com/?page_id=829>
cheers Darrel
It is sensible question and the simple answer is yes, they do to both questions.
You do need to go a little bit deeper, and make some attempt to quantify the different factors that reduce, or increase, dissolved oxygen levels.
When plants are actively photosynthesising they produce oxygen from:
carbon dioxide + water + light energy → glucose + oxygen + water
(6 CO2(gas) + 12 H2O(liquid) + photons → C6H12O6(aqueous) + 6 O2(gas) + 6 H2O(liquid).
In floating plants most of this oxygen will be lost to the atmosphere, although some will go into solution.
All plants will also take up NH3, NO2 and NO3, and any NH3 and NO2 that doesn't go into the nitrification (which is an oxygen intensive process) will help maintain dissolved oxygen levels.
The demand for oxygen of the water/fish/tank/microbes/plant system can be described by its Biochemical Oxygen Demand (BOD), but unfortunately we can't easily measure this, although we can estimate it.
As a general rule tanks with plants will maintain higher dissolved oxygen levels and better water quality even when the plants aren't photosynthesising (at night), until the plant biomass significantly reduces both flow and surface area.
Other than photosynthesis the major way that oxygen enters the water column is through diffusion at the gas exchange surfaces. Because diffusion occurs over a gradient, we need a water surface that is as large as possible.
We can make the active gas exchange surface of the tank larger by having a rapid turn-over of water, so that there isn't time for the surface layer to become saturated with oxygen before "new" water replaces it at the surface.
Ideally we would like to make the surface much, much larger, which is what a wet and dry trickle filter does. If we used this type of trickle filter, we could to a large degree ignore all the other variables.
As a rule of thumb, in a tank for rheophilic fish, that doesn't have a trickle filter, you need to make sure that the floating plants/leaves don't cover more than 1/2 the surface area in any tank.
As the BOD increases (larger fish load per tank volume, carnivorous fish with a high protein diet), we need to try and make both flow and gas exchange surface as large as possible, whilst also ideally maintaining a large plant biomass. These competing requirements may mean that some plants need to be in a separate sump, possibly with a reversed lighting regime.
This is covered in more detail in: <http://plecoplanet.com/?page_id=829>
cheers Darrel
@ Auspleco, Just normal everyday supermarket skewers, thin ones, they come in packs of fifty or more..You need to visit Mooo Mooo's Shaun, come on down lol I gots frogbit you can have, and pretty shrimpies to enhance your gene pool(they aren't free tho ) ..It's not that far..
) ..It's not that far..
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gosh! i thought my presence alone owuld get me some freebies loland pretty shrimpies to enhance your gene pool(they aren't free tho
I have been following this thread and it has thrown up of questions I had but better than that I got answers and my long debate of should or should I not had been answered with a resounding yes! O only thing its I don't know where the best place to get it from is? Ebay has lots of people selling it but having the suspicious mind I do,I don't want to buy it from there as they could of just scooped it out of there pond!
big bird mentioned about half a leaf and it will survive-my pond agrees! From no where it is covered got there the same way a metre square of strawberries got in my garden-from the winged creatures above
Respect and thanks for any ideas
Cc
big bird mentioned about half a leaf and it will survive-my pond agrees! From no where it is covered got there the same way a metre square of strawberries got in my garden-from the winged creatures above
Respect and thanks for any ideas
Cc
Started to remove some of my duck weed. Just back from a week holiday and it's coverd the hole tank, will only leave a 1/4 off it in the tank from now on.
Moo makes a mean choclate cake and is a fun person, worth the trip alone.
Back to the duckweed. Yup I would also leave about 1/4. cheers jk :thumbup:
Back to the duckweed. Yup I would also leave about 1/4. cheers jk :thumbup: