Nitrifying bacteria lifespan

[M0oN]

Now that I've got my tank heavily planted I'm wondering how long I should expect to wait before the nitrite begins to decline, it's at 2.0 ppm right now but as far as I know the plants get to ammonia before bacteria do?

Any thoughts?

[brewmaster15]

Hi Jason,
If you are running a filter in that tank...Your Biofilter breaks down ammonia and Nitrite in the same filter media..so ammonia goes to Nitrite to Nitrate all in the same spot. What you are seeing as a nitrite spike is what happens when a tank is cycling.. You see an ammonia spike first , then a nitrite spike. In days, or weeks depending on your tank set up The bacteria that converts nitrite to nitrate will increase to the point that you will have no nitrites in the tank and will start reading nitrates unless your plants are removing the nitrates.

Hth,
al

[M0oN]

So basically since the cycle's already begun the plants will only help to speed up the process at best?

My tankw on't be stuck in an eternal cycle because of the plants absorbing nitrate will it?

Thanks Al :)

[Carol_Roberts]

I have no idea about plants. You might get a better response in the biotope section.

I would suggest you measure your nitrate now and every 4 hours so you can chart how the levels decline in your tank.

Remember too that nitrate is only one of many things that accumulate in the water. Plants don't remove fungus spores, bacteria, cysts, etc.

[brewmaster15]

Jason,
Actually your plants will do a great job of removing the end product of biological filtration..your Nitrates. Its basically what we accomplish with water changes and in many cases terrestrial vines like pothos and philodendrons roots. In theory if your planted tank is well established you will not have any measurable values for ammonia, nitrite, and nitrate.

I think Carol's suggestion is good to ask this in the biotope section...so I am moving it there.

-al

[M0oN]

Thanks for moving it Al.

The problem is I had the tank getting established before adding the plants, it was in the process of cycling and going through it's nitrite spike.

Logic told me that by adding a lot of plants, I would remove the ammonia before the nitrite could break it down, thus choking them off from any source of food and the end result owuld be them slowly dying...

I know that it wouldn't happent o ALL the bacteria in the tank, but I expected it would at least make the levels decline drastically...

Now I'm somewhat confused hehe, so I guess everyone's opinion would be the best place to start :) Will leaving the tank alone and just performing regular maintenance lead to it eventually cycling and all of the toxins declining?

Thanks.

[M0oN]

On another note, I've noticed all of the hitch hikers that were on the plants were spending most of their time at the very edge of the top of the water in the tank on the first day of introduction (snails), while my pH is being altered to 6.2 by injecting co2, I haven't yet begun to mess with the gH in the tank, so it's reading at around 21...

This morning I saw but one trumpet snails hanging around at the top lip and I'm wondering if their behavior is a result of being thrown into such a low pH without acclimation or if it's because their shells are melting? (I was under the impression that acidic waters made their shells melt, not low pH...)

[rdeis]

I'm no expert, bit I've just completed the startup cycle on my 60 gallon corner tank so maybe my story will help.

The ammonia and nitrite spikes were *very* small.

I wouldn't call it "heavily planted" compared to others I've seen, but more of a light-medium. We have 2 java ferns, 2 vals, 2 spiral crypts, 1 wendetti crypt, 6-7 red hygro, 5 water sprite, 2 red melon swords, and one amazon sword.

At the reccomendation of the LFS, we added Nitromax according to the directions on the bottle. Can't say whether it helped for sure or not.

Starter fish included 4 diamond tetras and 5 zebra danios.

After a week or so, the tank was replete with Fuzz/lawn algea, so we added 4 SAEs, who made short work of it.

Around day 10 the nitrite hit .3ppm, then it fell back to zero. I use a couple of different test kits and compare results- and 1 of the three never detected them at all.

Ammonia readings were similarly small throughout- small enough that I can't really say I detected a "spike".

I think my Nitrates were up to about 20ppm by day 14, when I did the first water change and dosed trace minerals.

Now I'm about a month in and the crypts are reproducing. I've added 6 Otos, who are doing a great job keeping the brown algea in check, and I'm still figuring out the fertilizer schedule.

This week the tetras and danios get replaced by farowellas and amano shrimp, and I'll leave it there until I have the plant thing figured out and stable.

[M0oN]

I'm no expert, bit I've just completed the startup cycle on my 60 gallon corner tank so maybe my story will help.

The ammonia and nitrite spikes were *very* small.

I wouldn't call it "heavily planted" compared to others I've seen, but more of a light-medium. We have 2 java ferns, 2 vals, 2 spiral crypts, 1 wendetti crypt, 6-7 red hygro, 5 water sprite, 2 red melon swords, and one amazon sword.

At the reccomendation of the LFS, we added Nitromax according to the directions on the bottle. Can't say whether it helped for sure or not.

Starter fish included 4 diamond tetras and 5 zebra danios.

After a week or so, the tank was replete with Fuzz/lawn algea, so we added 4 SAEs, who made short work of it.

Around day 10 the nitrite hit .3ppm, then it fell back to zero. I use a couple of different test kits and compare results- and 1 of the three never detected them at all.

Ammonia readings were similarly small throughout- small enough that I can't really say I detected a "spike".

I think my Nitrates were up to about 20ppm by day 14, when I did the first water change and dosed trace minerals.

Now I'm about a month in and the crypts are reproducing. I've added 6 Otos, who are doing a great job keeping the brown algea in check, and I'm still figuring out the fertilizer schedule.

This week the tetras and danios get replaced by farowellas and amano shrimp, and I'll leave it there until I have the plant thing figured out and stable.


Thanks for the reply Rdeis.

My problem is that before I even planted the tank it had already beguni t's cycle and the filter bed was full of half the bacteria needed to complete the cycle.

Ammonia levels were at zero, nitrite was high, I never bothered to check nitrate...

Guess I'll have to see what happens :)

[rdeis]

Well, given that a completed cycle has appropriately sized colonies of both types, I would expect the worst case is that the Nitrate colony reduces to an appropriate size given the plant load as the Nitrate colony grows.

Even after extablishing the cycle the colonies will change size- bigger with more fish load, smaller with more plant load. That's why the rule of thumb says to increase fish load slowly-- so the bacteria colonies have time to catch up without creating spikes.

If you do a fishless cycle, you theoreticly have colonies that are larger than your max fish load would require, and once you add fish they die off to match the demand.

Like you said- should be fine, just have to watch the levels and see.

[ChloroPhil]

MoON,

Some pretty conclusive studies have been done with aquatic plants regarding preferrence of Nitrogenous chemicals. It's been shown that plants prefer Ammonium (NH4) over Nitrite or Nitrate. Chemically, Ammonium is less stable than NO2 or NO3 and is easier for the plant to break down.

What this means for people with planted aquariums is that in tanks with heavy plant loads there is a very small "cycle" and that it takes some time for it to happen. In effect, your plants are taking the place of the Nitrifying bacteria which is why we need to add fertilizers to our plant tanks. Don't worry about the bacteria though, they will colonize your filter and eventually the leaves of your plants (LOTS of surface area). As long as you keep up with your water changes, to keep your nutrients in balance, you'll be alright.

Best,
Phil

[brewmaster15]

Hi Phil,
I have seen references to ammonium like that as well ...But thats assuming that it is ammonium in the tank and not ammonia Right? Do you know if ammonia is treated similar to the ammonium?

The form Ammonia or ammonium is dependent on pH. Do plants use both equally well?

thanks,
al

[M0oN]

Well I'm happy to report that the plants seem to have settled in and the nitrite levels went from 3.0 to .50 over a 48 hour timespan from introducing the plants.

I'm very pleased with these results and not so worried anymore...

On another note, I introduced two large davidsansi cory cats to my tank using the drip method, our tap water is around 7.8 pH, I dripped water into a bucket of regular tap water with the fish in it at around 2 drops per second over 1 hours time and introduced them. The water in the planted tank is 6.2 pH.

This morning they were very very lethargic, laying on plants at odd angles and such, I thought they were dead at first and went to remove them, but they slowly swam away under a cave. I'm wondering if since they've gone 24 hours will they probably survive? What can I do to help their chances, if anything?

Perhaps I'm injecting too much co2 and starving them of oxygen overnight? (although cory cats are low level oxygen fish and I would think the platty's, oto's and praecox rainbows would be showing signs of stress before they would, but they're all perfectly fine). My kH is at 9 and I'm injecting enough co2 to lower the pH from 7.8 to 6.2...oddly enough the co2 doesn't turn on until around 3 in the morning rather then during the day when plants are using it most?

What are your thoughts?

[ChloroPhil]

Al,

Plants prefer Ammonium, but they'll use Ammonia readily. So much so that I make sure to have a bunch of floating plants in a tank after I mess with the substrate a lot to use up the Ammonia/um that is produced soon after from the kicked up mulm.

MOoN,

If your KH is 9 and you've got a pH of 6.2 your tank is running at approximately 120ppm of CO2! That's dangeous my friend, you want your pH to be 7.0 with that high of a KH. I'd do a water change to get as much of that stuff out of there as you can. Let the pH stabilize overnight and then start your CO2 up again, slowly this time.

[M0oN]

Al,
I'm not sure if all of this is just common knowledge to you, but in my book "Ecology Of The Planted Aquarium" by Diana Walstad she states the following:

Aqatic plants can use ammonium (NH4+), nitrite (NO2-) or nitrate (NO3-) as their nitrogen source. Many aquatic plants have been found to prefer ammonium over nitrates, and the extent of this preference is substantial. For example, Elodea nuttallii growing in a mixture of ammonium and nitrates, removed 50% of the intial ammonium after 8 hr but few nitrates. Only when much of the ammonium was gone did it begin to take up nitrates.

There is a graph below showing that after 32 hours Ammonium levels went from 2.0 to under 0.5, while Nitrates did not start to decline until 16 hours later, when Ammonium had been depleted to 0.5, at ths point the nitrates slowly decline to 0.5 over 64 hours time.

Plants (0.5 g dry wt.) were placed in 1 liter of filtered lake water containing 2 mg/l each of NO-3N and NH4-N. Concentrations of ammonium and nitrates wer measured at 4, 8, 16, 32 and 64 h. For each exposure period, 3 tanks with plants and 3 control tanks without plants were used. Control tanks (without plants) showed that there was little loss of either NH4-N or NO3-N due to bacterial processes.

Aquatic plants take up ammonium more quickly than nitrates. For example, the turnover time for ammonium (at .4 pm N) in Pistia stratiotes was found to be just 4 hours, while nitrate turnover required a full 20 hours.

Ammonium often inhibits nitrate uptake and assimilation in a variety of organisms. For example algae doesn't take up nitrates if the ammonium concentration is more than 1 uM (.018 mg/l). The prompt cessation of nitrate uptake when ammonium is added to nutrient solutions has been investigated extensively in duckweed. The inhibition is typically reversible in that plants will take up nitrates a day or two after all ammonium is removed from the water.

Of 33 aquatic plant species investigated, most were found to prefer ammonium over nitrates. Because many terrestrial plants grow better with nitrates and some botanists successfully grow plants with nitrates should not weaken the fact that aquatic plants - given a choice - greatly prefer ammonium. Whether they grow better with ammonium is a seperate issue - one that is not as critical to fish health or aquarium functioning. However, I would hypothesize that most aquatic plants probably grow better with ammonium.

If you're interested the full name of the book is "Ecology of the Planted Aquarium; A Practical Manual and Scientific Treastise for the Home Aquarist" by Diana Walstad...while I'm still new to the planted world, this book is full of information and I mean FULL of information. I'd suggest anyone buy it just for the sake of getting some new ideas and theory's on how plants work in an ecosystem...

This was just a quarter of a page taken from the book, there are about 30+ pages that elaborate on the uptake of ammonium versus nitrate etc. in the book...

[M0oN]

Al,

Plants prefer Ammonium, but they'll use Ammonia readily. So much so that I make sure to have a bunch of floating plants in a tank after I mess with the substrate a lot to use up the Ammonia/um that is produced soon after from the kicked up mulm.

MOoN,

If your KH is 9 and you've got a pH of 6.2 your tank is running at approximately 120ppm of CO2! That's dangeous my friend, you want your pH to be 7.0 with that high of a KH. I'd do a water change to get as much of that stuff out of there as you can. Let the pH stabilize overnight and then start your CO2 up again, slowly this time.


Is there a formula you can give me related to ppm levels and kH levels in water? What level is harmful to fish? I have access to RO water and will likely be using it anyway to induce spawning in my apistogramma...so I may need to do some tinkering around...

Thanks Phil :)

[ChloroPhil]

MoON,

Check out this reference table.

http://www.sfbaaps.com/reference/table_01.shtml