Fishless Cycle/Planted Tank question

FreshwaterJeff

FreshwaterJeff

Superstar Fish
#1
Mar 28, 2006
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#1
Alright, time for me to feel like a newbie again :D

All along I've been planning on fishless cycling my planted tank later this summer, when it came to mind (thanks to a comment on another thread) that if I planted the aquarium while cycling, the lack of nitrates at the outset might be detrimental to my plants.

This makes logical sense to me, but my first question is whether this is a valid concern. Is it?

Assuming it is, I've quickly brainstormed two ways around this potential problem:

(a) I could start the cycle before putting in the plants, and then plant once my nitrates start to build, or

(b) I could go ahead and plant the tank as planned (i.e., at the outset), and dose nitrates until the cycle progresses to the point that nitrates are building.

Please let me know what you think. My first concern with (b) is that it's a recipe for huge algae growth...
 

FreshwaterJeff

FreshwaterJeff

Superstar Fish
#2
Mar 28, 2006
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#2
Alright, just did some more research...

Based on the description of Flourish Nitrogen, it appears that plants may actually prefer to get their nitrogen from ammonium...

http://www.drsfostersmith.com/Product/Prod_Display.cfm?pcatid=9904&N=2004+113221

"Supplies nitrogen, one of the three main macro-nutrients required by plants, in both the nitrate form and the plant-preferred ammonium form. Does not release ammonia. 250 ml treats up to 5,000 gallons."

So, here's my next question: can plants fulfill their nitrogen needs from the ammonia added in fishless cycling, or would it have to be ammonium instead?
 

hcover

hcover

Medium Fish
#5
Apr 22, 2006
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#5
is that true?

rohnds said:
There is no need to cycle a planted tank. You should be able to add fish immediately. Plants are better at consuming NH3 than nitrifying bacteria.

Rohn
Click to expand...

Is that true? I would think you'd at least need some filter media, gravel, or something with the good bacteria.

If it is true, I'm excited because we're planning a 75 gallon planted tank. I already have the tank, filter, and plants growing in another tank until the stand is ready and I have gravel, driftwood, etc.

hcover
 

FreshwaterJeff

FreshwaterJeff

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#7
Mar 28, 2006
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#7
Are you all sure?

Forgive my skepticism, but something about "Oh, it's a planted tank, it doesn't have to cycle" doesn't seem quite right to me...

I guess if I'm this skeptical, I can just add ammonia pre-adding fish and seeing if the plants/accompanying bacteria reduce the level to zero overnight...
 

Avalon

Avalon

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#9
Oct 22, 2002
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www.davidressel.com
#9
There's a couple of different cycling scenarios that typically happen when starting a new planted tank.

A. When not seeding a tank with bacteria, plants will absorb NH3/NH4, NO2, and NO3. Depending on how many you add, how fast they grow, type, CO2/no CO2, light, etc., will determine the amount of cycle you will see. Plant lightly and you will see a cycle, however it should be reduced (albeit still not safe). Plant heavily and you may not see one at all. There are too many factors involved to say "yes" or "no" to whether it will be fish safe or not.

B. Seeding the tank w/ bacteria along with planted tanks can be helpful, and is typically the chosen method, but not for cycling reasons. Bacteria is critical in the breakdown and assimilation of nutrient sources for plants, particularly in the substrate. This will also reduce the cycling duration and amount, and will usually show up as a major NO3 spike. I recently set up my 10g this way, and was measuring 80+ppm NO3 after about 2 weeks. Of course, water changes can take care of that, but the point here is that the plants I had just planted were in no shape to absorb the NO3 they would be capable of if they were adjusted and growing well.

To answer Jeff's questions, plant immediately, and as heavily as you can. You can toss plants out later (in fact you will have to). There are 2 sides to the fert thing--fertilize now or wait. For new plant keepers, I say wait for 2 weeks and use water changes (twice per week, 30-50%). This will really help avoid some algae issues, or at least put them off a little longer so the plants can get a chance to adapt to their new enviornment. Most experienced plant keepers will fertilize from the start. I do, but here's why: I typically use clippings from another tank that are already ready to grow, so they don't need much of an adjustment period. I set the new tank up with CO2, seeded filters, and high light. Make sense? If I start a new tank from other people's clippings or new plants from the LFS, then I'll wait on fertilizing until I see lots of new growth, and then I dose small amounts until the plants are chugging right along.

Oh, and plants don't really prefer ammonium over nitrates. In some cases they do, but you will never (I hope not anyway) see those cases in an aquarium. If they did, you'd hear everyone rant and rave about ammonia fert liquids and such. Everyone uses NO3 in the form of KNO3. The use of a good biological filter is to act as a buffer when NH4 spikes due to fish and such. I don't think plants are any better at absorbing ammonia than bacteria are at nitrifiying it. If that were the case, planted tanks with cheap power filters would never get green water. So, don't skimp on the biofilter, and don't worry about ammonia; it's bad, and always will be bad in aquariums.
 

P

prushing

New Fish
#11
Mar 3, 2006
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#11
I started my first tank in a long time, it has been up for over a month, I planted it starting out, left it for 1 week, and then started adding fish. I never got any nitrates or ammonium readings.
 

FreshwaterJeff

FreshwaterJeff

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#12
Mar 28, 2006
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#12
prushing - You wouldn't get ammonia readings without fish, because it's fish waste that causes ammonia. Similarly, without ammonia, you wouldn't get nitrite readings, and without nitrite, you wouldn't get nitrate - at least not until you started adding fish.

I would think you would get nitrates now, though - unless the plants are just gobbling them up...
 

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