plant aided nitrate reduction

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esoxlucius

Balaclava Bot Butcher
MFK Member
Dec 30, 2015
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Up until 3 weeks ago i didn't have any greenery anywhere near my tank to aid nitrate reduction. My tank nitrates would be 5ppm after a water change. It would take about 6 days for the nitrate to reach 20ppm at which point i'd do another water change and i'd be at 5ppm again until, over the next 6 days it would creep up to 20ppm again. This has been my cycle with my current stock and feeding regime etc etc for months now. 3 weeks ago i put about half a dozen small plants down in my sump. They are thriving even though the only light they have is 12 hours a day of unnatural strip lighting. The roots are really getting everywhere so i'd have thought that maybe my nitrate increase would slow down and even might stretch my water change to once every 7 or 8 days instead of every 6 days. But no, my nitrates still hit 20ppm 6 days after my water change. This tells me that yes the plants may absorb nitrates but maybe not as much as people say. Have any of you guys had similar results to me or maybe some of you have experienced noticeable nitrate reduction?
 
What plants are you using? I have heard that a lot of aquatic plants don't really do much for nitrate reduction. I think that a lot of people have been using the pothos plant with good results. It is not an aquatic plant so the leaves have to stay above water but it requires very little light and soaks up nitrates quite well.
 
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It was just my luck that the garden centre i usually go to didn't have any pothos on the day i went. An assistant pointed me in the direction of some seedlings that he said were similar to pothos, i can't remember the fancy name they have but the leaves are very much like the pothos and like i said they are thriving. They are still relatively young so maybe i might see a marked difference in a few weeks when they get even bigger.
 
People have done testing on the impact of Pothos, both on this site and on other sites. I actually helped do some of the calculations in the thread (sticky) on it. They do have a significant impact on nitrates.

That doesn't mean that any and all types of plants will work as well. Plants don't all utilize nutrients in the same manner, and certainly not under the same lighting conditions. Having root systems submerged in water 100% of the time throws another variable in the mix. Lastly, aquatic plants likely utilize nutrients differently than terrestrial plants.
 
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I've heard good things about frogbit. It grows on the surface, and you just pull some of it out when it becomes overgrown.
 
I have read that plants actually prefer ammonia, only using nitrate as a secondary source if ammonia is not available. If heavily stocked with available ammonia nitrates would never be affected. I'm sure this also depends on plant types etc.....
 
I have some pothos, but also have water lettuce. If you have good lighting water lettuce grows like crazy. I have to pull handfuls out every week, it even grows faster than the macro algae I used when reefkeeping. The more you have to toss = more nutrient your pulling out. The pothos is growing, but not nearly the same biomass increase each week.
 
It was just my luck that the garden centre i usually go to didn't have any pothos on the day i went. An assistant pointed me in the direction of some seedlings that he said were similar to pothos, i can't remember the fancy name they have but the leaves are very much like the pothos and like i said they are thriving. They are still relatively young so maybe i might see a marked difference in a few weeks when they get even bigger.
was it Philodendron?
 
I think the key is mixing different types. Pothos with an oxygenating grass of your choice and a floating plant. Increase light intensity and photoperiod and you'll see a marked difference.
 
In the unlikely event that we all have thriving jungles in our set ups and our nitrates are permanantly at 0ppm, what happens then? The plants can't thrive any longer without the nitrates and will wither. Does this mean that we then have to put nitrate supplements back in our tanks to keep them healthy? If thats the case whats the point in going to the trouble in the first place? Also, does 0ppm nitrate mean we don't need to do water changes anymore, absolutely not because we still need the micro nutrients and trace elements in our tanks that only regular partials can give us.
I'd say that total nitrate absorption by plants is bad, that's if you want to keep them healthy, though partial nitrate absorption is good because, although it will never get us away from water changes, partial absorption will prolong the time in between them. Would that be a realistic summing up of plants in the aquarium or or there other sub plots i'm missing?
 
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