Ask Questions About Cycling

[webunit]

I've read the article on cycling a tank before adding fish and I'm wondering why is it recommended to do a "water change" after ammonia and nitrate read zero and just before adding fish?  Also please define "water change" -- how much and how to do it.
 
Thank you very much,
webunit

 

[stanleo]

You need to change the water because by then the nitrates (nitrites are what you want to be 0ppm) will have risen to near dangerous levels so you need those to drop, and the only practical way to do that is through a large water change. As for how much that really depends on how high the nitrates are and how low you want them to be depending on what you are going to keep.
 
If your nitrates have risen to 40ppm and you want them at 20ppm, then change 50% of the water. Remember to temp match and use a dechlorinator. That's assuming of course your tap water has 0ppm nitrates to begin with.

 

[TwoTankAmin]

It goes beyond nitrates. During a cycle one should change as little water as possible. By the end of the cycle things are not in the ideal condition for the fish. Somethings we want in the water may be missing as well as there being other stuff we don't. The temperature may be higher than desired and big changes correct that fast.
 
A large water change means as much as you can. You siphon out the water in the tank use it for your garden or throw it out and then replace it with new dechlorinated water.

 

[Sumatra]

Hello,
 
I have been posting my test results up in my 'Betta Journal' but I figured I'd post them up here for you guys to have a look at. Any advice on what I may be doing right/wrong would be much appreciated as I am completely new to this whole thing. My tank is a 55L Aqua Nano One. 
 
Tap Water
 
P.H. - 7.2
Ammonia - 0ppm
Nitrite - 0ppm
Nitrate - 10ppm
 
Initial Tank Start-Up (Day 1)
 
P.H. - 6.8
Ammonia - 0.25ppm
Nitrite - 0ppm
Nitrate - 5ppm
 
Amount of Ammonia added - 2ml
Ammonia reading - 4ppm
 
I am aware that 4ppm is higher than what was needed. I did aim for 3ppm but I obviously ended up going over.
 
Day 4
 
P.H. 7.0
Ammonia - 2ppm
Nitrite - 0.25ppm
 
Day 7
 
P.H. - 7.0
Ammonia - 2ppm
Nitrite - 2ppm
 
I also tested my GH/KH and Phosphate levels:
 
KH - 2dKH (very low!)
GH - 9dGH
Phosphate - 0
 
I was worried about my KH level being so low and so I have been testing my P.H. periodically throughout the day/evening. It has remained at 7.0.
 
Edited because I missed out some information.

 

[TwoTankAmin]

You started with 4 ppm of ammonia and 4 days later it had dropped to 2 ppm, all fine and good. But then you report the nitrite on day 4 as .25 ppm which is not possible. 2 ppm of ammonia produces just over 5 ppm of nitrite on most hobby kits. But your test report is for only .25. Something is not quite right.
 
Next, if your tank was able to clear 2 ppm of ammonia between adding it and the day 4 test, this rate should at least be maintained and more probably accelerated. But on day 7 you still have 2 ppm, unchanged for 3 days while the nitrite finally starts to move up, but nowhere near the level it should be.
 
Also, you fail to mention what strength ammonia you are using. You added too much because you probably failed to do two things- 1. Reduce the tank volume to allow for decor and substrate etc, and, 2. with a real .25 ppm of ammonia in your tap, you need to add only 2.75 ppm to reach the suggested 3 ppm level.
 
I am wondering did you seed the tank with bacteria in any fashion? That means did anything going into the tank come out of an established tank or are there any live plants in the tank. Also, what brand test kits are you using?
 
Also your results for nitrate serve to reinforce the fact that it is one of the least accurate test kits. If your tap has 10 ppm of nitrate, how can your tank, which you filled with 10 ppm water only have 5 ppm in it? It takes eather water changes or live plants (or algae) to remove nitrates from a new tank.

 

[stanleo]

Today is day 9. I tested and the results are Ammonia 0ppm, Nitrite over 5ppm and Nitrate is 40ppm. According to the article if I get another reading of 0ppm ammonia day after tomorrow I need to add a snack dose for dose 3 of 1/3 the original amount. Is that right? If you need to know the history of the cycle, there is a link to my journal in my signature.

 

[TwoTankAmin]

Yes that would normally be correct when the directions are followed. However, The normal progression for a planted tank is first you plant it and then you wait about two weeks for the plants to start settling in before worrying about cycling. There are a number of reasons for this but one good one is plants can be harmed by too much ammonia, they do not like nitrite particularly either. Plus, depending on planting etc. ammonia additions can result in algae. Cycling and plants is a much more detailed process. Usually one uses a lower level of ammonia because plants will consume ammonia (in the form of ammonium).
 
Before you add any more ammonia can you do a diluted nitrite test so we can be certain what level it is at? Directions on how to do diluted testing can be found in the article here http/www.fishforums.net/index.php?/topic/433778-rescuing-a-fish-in-cycle-gone-wild-part-il/

 

[stanleo]

I will have to go to the store tomorrow for the water to do the diluted test.  
 
I ordered my plants and they are coming in the morning. I have no place to put them other than in this tank. I had no idea that you should plant first and then do the cycle. I must have missed that in my research. Should I Go ahead and plant them and then just hold off on the cycle?

 

[Sumatra]

You started with 4 ppm of ammonia and 4 days later it had dropped to 2 ppm, all fine and good. But then you report the nitrite on day 4 as .25 ppm which is not possible. 2 ppm of ammonia produces just over 5 ppm of nitrite on most hobby kits. But your test report is for only .25. Something is not quite right.
 
Next, if your tank was able to clear 2 ppm of ammonia between adding it and the day 4 test, this rate should at least be maintained and more probably accelerated. But on day 7 you still have 2 ppm, unchanged for 3 days while the nitrite finally starts to move up, but nowhere near the level it should be.
 
Also, you fail to mention what strength ammonia you are using. You added too much because you probably failed to do two things- 1. Reduce the tank volume to allow for decor and substrate etc, and, 2. with a real .25 ppm of ammonia in your tap, you need to add only 2.75 ppm to reach the suggested 3 ppm level.
 
I am wondering did you seed the tank with bacteria in any fashion? That means did anything going into the tank come out of an established tank or are there any live plants in the tank. Also, what brand test kits are you using?
 
Also your results for nitrate serve to reinforce the fact that it is one of the least accurate test kits. If your tap has 10 ppm of nitrate, how can your tank, which you filled with 10 ppm water only have 5 ppm in it? It takes eather water changes or live plants (or algae) to remove nitrates from a new tank.

 
I do have live plants in the tank with Co2, yes. Also, there isn't actually any ammonia in my tap water. The initial reading of ammonia was actually due to my substrate, which does leach a small amount for the first two weeks or so. My plants were settling in my tank for just over two-weeks before I began my cycle. 
 
I'm using the API Test Kit and it is brand new. I tested multiple times (as I always do) to ensure that each reading I was getting was correct, and it was. All readings came out the same. Everything is in date and I used both used and new tubes to ensure that nothing was interfering with the results I was getting. 
 
I realise that I did go over with my initial dosing but this is my first time cycling a tank and mistakes will obviously be made.
 
I'm going to test again in the morning to see if my ammonia has dropped.

 

[TwoTankAmin]

The plants change things in any cycle because,among other things, they both consume ammonia and also have some of the needed bacteria on them.
 
So the methods for any needed cycling change with their presence. The first noticeable difference is in all the numbers when one tests.
 
1. Some of the drop in ammonia one sees is due to plants. The more plants one has, the less any drop is due to bacterial processes.
2. When plants use ammonia directly, two things do not happen:
    -There is no nitrite and there is no nitrate created from the consumption of this ammonia.
    -Any nitrate created by the bacteria may be consumed in part or completely by the plants.
3. Setting up the tank changes as the plants should go in first and be allowed to establish for a while before determining if any cycling is needed.
4. Algae may become an issue depending on the plants and tank involved.
5. The total time to make a tank fish ready will be shorter.
6. Some plants can be harmed by ammonia levels typical of fishless cycling.
 
Whether one is going to do some cycling or merely plant and stock, one should almost always allow the plants to settle in before the fish are added. The one obvious exception is when its only plants that are attached to things or floating rather than planted in the substrate.
 
If you cycle then plant you need to let the plants settle in before he fish are added. So you will need to backtrack some and make sure the tank is still fish safe after the plants are in for a bit. The easiest way to test for this is to add 2 ppm of ammonia and then test in 24 hours. Do not add more than 2 ppm. Depending on one's readings for ammonia and nitrite after 24 hours one will have a good idea of how to proceed.

 

[stanleo]

Yes that would normally be correct when the directions are followed. However, The normal progression for a planted tank is first you plant it and then you wait about two weeks for the plants to start settling in before worrying about cycling. There are a number of reasons for this but one good one is plants can be harmed by too much ammonia, they do not like nitrite particularly either. Plus, depending on planting etc. ammonia additions can result in algae. Cycling and plants is a much more detailed process. Usually one uses a lower level of ammonia because plants will consume ammonia (in the form of ammonium).
 
Before you add any more ammonia can you do a diluted nitrite test so we can be certain what level it is at? Directions on how to do diluted testing can be found in the article here http/www.fishforums.net/index.php?/topic/433778-rescuing-a-fish-in-cycle-gone-wild-part-il/

I put the plants in today. Then i took for a couple hours and then went to get the distilled water and did a diluted test. On a whim I test the tank water straight. The funny thing is the nitrite tested 0ppm. Yesterday it was off the chart over 5ppm. I did the test twice yesterday and twice today just in case I did something wrong and the test was consistent. I can't imagaine that the plants absorbed all that nitrite just in a couple hours. So what is going on? 
 
I am going to test tomorrow for everything again. If the ammonia is again 0ppm and the nitrite is again 0ppm, should I go ahead and do a snack dose for dose #3 or should I wait a couple weeks? It won't bother because I wasn't planning to buy the fish for at least 2 more weeks anyway. I want the plants to have time to root and I am going to start CO2 injection so I want to ensure I get that set right before I put the fish in. 

 

[eaglesaquarium]

Plants don't really use nitrite at all, so chances are:
 
* your first reading wasn't quite as high as you tested yesterday... or
* your new reading isn't quite as low as you tested today... or
* your nitrite bacs got themselves into gear to finally munch through the nitrite.
 
Nitrite can fall rapidly, as 1ppm ammonia is actually ~ 2.7 ppm nitrite (because of the molecular masses of the different ions), but when the bacteria 'use' it, they use a heavier ion (nitrite) than the ammonia bacs (ammonium), and the result is that the nitrite level can drop dramatically fast once the nitrite bacs are in place, just as the ammonia level can drop from 2ppm to 0ppm rapidly, the nitrite levels can go from 5ppm to 0ppm just as fast (because 2ppm ammonia is basically the same as 5ppm nitrite, when you consider the conversion rate is based on the molar mass).
 
How long have you been seeing nitrite in the tank before this?

 

[stanleo]

I saw nitrite when when I tested on day four of the cycle at 2ppm. By the time I tested on day 7 it was over 5ppm and stayed that high until today. This does seem to be going a lot faster than the article suggested, is that because the media and decor are from my old tank even though it all as sat dry for two months?

 

[eaglesaquarium]

Its possible that some of the bacteria might have survived, as what is 'dry' to you and what is 'dry' to the bacteria are not always the same thing.  Not many of the bacteria will have survived, most likely, but even a small boost can make a big difference.

 

[TwoTankAmin]

Dubious that it went down that fast for real.