Nitrates Going Down On Their Own?

[ellena]

Only just starting my cycle. Got a bag of gunk from a mature filter yesterday and put in in my tank which was up to temp, filled with declorinated water with filter running. Added 2ml of 9.5% ammonia (25l tank). Ammonia was 8ppm (although this was the highest reading, so maybe off the scale?), nitrates 10ppm, didn't measure nitrites.
This morning, tested it all again, ammonia still 8ppm, nitrites 0.25ppm, but nitrates down to 5ppm? I have 2 live plants in there, would they cause the nitrates to drop like that?
Thanks

 

[aaronnorth]

yes.

 

[ellena]

Fab! That explains it-thanks

 

[waterdrop]

The testing and feedback thing that we do during fishless cycling here in the "New to the Hobby" forum can be a little bit more difficult to follow (not necessarily all that bad, just a -little- more difficult) when you have a lot of plants in the tank. Plants will take up differing amounts of ammonia and nitrate (plants are capable of taking up ammonia, nitrite(NO2) and nitrate(NO3), but it varies greatly by species and conditions. Usually the preference is for ammonia first, then nitrates(NO3) to a lesser extent and almost never for NO2, although technically that can sometimes happen in very small amounts.) and so this constitutes another variable in the feedback you're trying to collect for yourself from the testing.

In fishless cycling its usually undesirable to allow the ammonia level to sit as high as 8ppm because that will encourage the wrong species of nitrifying bacteria to grow on the media surfaces in place of the species we want. This wrong species processes ammonia just like the correct species, so it appears to us that everything is ok. When the ammonia concentration drops a little lower, that wrong species will die but leave its biofilms in place and it will take a bit of time for the correct species to come in and replace it. Overall it just constitutes a slowdown in the fishless cycling process and doesn't stop the process from happening. This is why 5ppm is the correct concentration for fishless cycling.

~~waterdrop~~

 

[ellena]

Right, I'll do some water chaging tonight then to get it down to 5ppm. Is it possible that it could be more than 8ppm, off the scale? It did match the colour on the card pretty well, not stronger or darker or anything.

 

[ellena]

Right, 50% water change done, ammonia down to 4ppm
Will the high ammonia have done any damage to the bacteria in the 'gunk' I added from the mature tank?

 

[waterdrop]

No, I'm sure you're fine. The fact that you had MM makes it even less likely that any high-ppm species really had a chance to get started.

~~waterdrop~~

 

[P&J]

Also keep in mind that the nitrate test can be a little tricky (speaking of experience with the API drops) because it is more complex than the other common tests. Also, I, personally, have difficulty reading the tiny differences between some of those colors and wouldn't be surprised if I tested it at 10 one minute and 5 the next.

At this point in my cycle, I wasn't even testing for nitrate. I simply watched the ammonia go down, the nitrite go up, and then eventually go back down. Someone please correct me if I'm wrong, but isn't the only reason to test for nitrate so that you know when your otherwise off-the-chart nitrite is starting to go down?

-P

In fishless cycling its usually undesirable to allow the ammonia level to sit as high as 8ppm because that will encourage the wrong species of nitrifying bacteria to grow on the media surfaces in place of the species we want. This wrong species processes ammonia just like the correct species, so it appears to us that everything is ok. When the ammonia concentration drops a little lower, that wrong species will die but leave its biofilms in place and it will take a bit of time for the correct species to come in and replace it.

Thanks for this info, waterdrop. I had heard that too high of a concentration would "stall" a cycle, but I never knew the science behind it. It got me thinking, though: Do you think this is one reason that some "serious fish people" don't believe that fishless cycling works? I can just see someone dumping a whole bunch of ammonia in, watching it go down, and then losing fish when the lower levels of ammonia aren't processed.

Sorry for the thread hijack ellena, I hope you don't mind!

-P

 

[fatheadminnow]

NitrAte is the final product to the Nitrogen cycle, which can only come from the breaking down of NitrIte.

It is not un-likely to have a NitrAte reading form your tap water as well, that is why it is always a good idea to test your tap water as well, just so you know where you are at.

Once NitrAte becomes present in a tank, that tells us that there is both types of Autotrophic bacteria in our filter. One types breaks down ammonia to nitrite, while the other breaks down nitrite to nitrate.

-FHM

 

[waterdrop]

Also keep in mind that the nitrate test can be a little tricky (speaking of experience with the API drops) because it is more complex than the other common tests. Also, I, personally, have difficulty reading the tiny differences between some of those colors and wouldn't be surprised if I tested it at 10 one minute and 5 the next.

At this point in my cycle, I wasn't even testing for nitrate. I simply watched the ammonia go down, the nitrite go up, and then eventually go back down. Someone please correct me if I'm wrong, but isn't the only reason to test for nitrate so that you know when your otherwise off-the-chart nitrite is starting to go down?

-P

In fishless cycling its usually undesirable to allow the ammonia level to sit as high as 8ppm because that will encourage the wrong species of nitrifying bacteria to grow on the media surfaces in place of the species we want. This wrong species processes ammonia just like the correct species, so it appears to us that everything is ok. When the ammonia concentration drops a little lower, that wrong species will die but leave its biofilms in place and it will take a bit of time for the correct species to come in and replace it.

Thanks for this info, waterdrop. I had heard that too high of a concentration would "stall" a cycle, but I never knew the science behind it. It got me thinking, though: Do you think this is one reason that some "serious fish people" don't believe that fishless cycling works? I can just see someone dumping a whole bunch of ammonia in, watching it go down, and then losing fish when the lower levels of ammonia aren't processed.

Sorry for the thread hijack ellena, I hope you don't mind!

-P

Yes, I'm sure the exact scenerio you describe has happened many times. And many other reasons. A different, very common scenerio with experienced fish keepers is that they've learned and still practice a very correct type of fish-in cycle and since that works for them they see little reason to switch. With large volumes of water to small numbers of fish, the number of water changes you need to perform to keep toxic levels safe are fairly few. Add lots of plants to that and the water is even more pristine for the fish who are in the cycle. The problems often come when they assume a beginner will be diligent about knowing and practicing all the necessary bits of a fish-in cycle. Often the full information comes late to the beginner.

~~waterdrop~~

 

[ellena]

I'm with you on the API tests, P&J-it is v.hard to tell sometimes.
I'm only tested the nitrates in tap water and then in the tank after a while out of curiosity.
Just doing ammonia and nitrites now. No movement since last night, although the ammonia did take longer to go green which I'm taking as a good sign