Ammonia Stopped Dropping, Thoughts?

[Dave26]

Hi all. I've cycled a couple of tanks before (a couple of years back) with no problems using the fishless method on this page. My current cycle seemed to be going fine, but there have been a few unexpected results. I think it's been cycling for between 4 and 6 weeks (probably 6 but I've lost count) and now ammonia doesn't seem to be being processed.

At first ammonia went down and nitrite didn't show on the API kit, in hindsight I think I overdosed ammonia and the nitrite went off the scale. A large water change seemed to resolve this and I had a nitrite spike. Ammonia seems to be processed very slowly but it was going down.

The last few days it's stuck at around 2ppm with no decrease (and no addition of ammonia), with today's readings below:






I can see that clearly all nitrite has been processed into nitrate, but the ammonia seems to have stayed constant for 3 days now. Is the nitrate stalling the cycle?

The heater is set to 28C, thermometer is showing just over 30C incase that's relevant. At this stage id expect 3ppm of ammonia to be processed fairly quickly...wouldn't i?

Any thoughts? Starting to get a little fed up!

 

[Ninjouzata]

Have you been testing your pH?

 

[Dave26]

Have you been testing your pH?

I did test it the other day and it was 6, which is the lowest that the test can read.

 

[Ch4rlie]

i believe that having a pH of 6.5 or below can actually make cycling a tank very difficult.
 
In fact, i think,  a ph of 6 will probably stall cycles, the bacteria cannot process in too low a ph.
 
There are things you CAN do to temporarily raise the pH for cycling a tank. However, i do not really know what would help to raise pH, hope someone can help with more advice about that.

 

[Ninjouzata]

Have you kept a record of test results that you could post? Also what tank size is this?

 

[Dave26]

i believe that having a pH of 6.5 or below can actually make cycling a tank very difficult.
 
In fact, i think,  a ph of 6 will probably stall cycles, the bacteria cannot process in too low a ph.
 
There are things you CAN do to temporarily raise the pH for cycling a tank. However, i do not really know what would help to raise pH, hope someone can help with more advice about that.

  
That doesn't sound great, fingers crossed!

Have you kept a record of test results that you could post? Also what tank size is this?

Sorry I haven't! It's 200l.

 

[eaglesaquarium]

 

Have you been testing your pH?

I did test it the other day and it was 6, which is the lowest that the test can read.
 

 
 
Bingo... pH crash.
 
1 - Do a 100% water change to remove the nitrates, which are responsible for crashing the pH in the first place.  (Once the nitrates build up too high, the buffering capacity of the water is compromised.  buffering capacity can be measured as 'kH'... and as the kH drops, the pH will fall as the acid.)
 
2 - You can raise kH  - Adding some calcium carbonate ('chalk') or some baking soda (sodium bicarbonate). 
 
 
But, before adding any, I'd suggest you measure your pH and let us know what that is - let the water sit for 24 hours to determine what your 'tap' water normally is.  The LFS can test it if you don't have a pH kit.  They can also test your kH for you.

 

[TwoTankAmin]

Bear in mind that when adding baking soda most fw tanks do not want or need the sodium part. African rift lake tanks are an exception. So it is important to do some big water changes once the cycle is done and before adding fish in order to get the sodium bout of the water.
 
The other thing to remember is that the bacteria use carbonates to as a source of the inorganic carbon they need to process ammonia to nitrate. That means they are using it up. And as it gets used up, KH drops, which will allow the pH to crash more easily with any build up of acids. Since one should minimize water changes during cycling, it is more common to have a pH drop then compared to an established tank in which we replenish a lot of things via weekly water changes.
 

 
To get a tank cycled in a reasonable amount of time, you need to make sure that, in addition to ammonia, the bacteria will also have:

• Lots of oxygen by keeping the surface of your water well agitated to let oxygen in.
• Inorganic carbon (as carbonates) by keeping your KH up. Do not let it drop below 3 dg (55 ppm).
• A good pH level by insuring it is above 6.5. The closer to 8.0 the faster the cycle will go. We do not recommend one alter their pH if it holds fairly steady anywhere between 6.8 - 8.5.
• An optimal temperature by having a heater set to between 75F and 85F. Lower tends to slow the cycle while higher won’t make things go even faster.

from http/www.fishforums.net/index.php?/topic/421488-cycling-your-new-fresh-water-tank-read-this-first/

 

[Dave26]

Have you been testing your pH?

I did test it the other day and it was 6, which is the lowest that the test can read.

 
 
Bingo... pH crash.
 
1 - Do a 100% water change to remove the nitrates, which are responsible for crashing the pH in the first place.  (Once the nitrates build up too high, the buffering capacity of the water is compromised.  buffering capacity can be measured as 'kH'... and as the kH drops, the pH will fall as the acid.)
 
2 - You can raise kH  - Adding some calcium carbonate ('chalk') or some baking soda (sodium bicarbonate). 
 
 
But, before adding any, I'd suggest you measure your pH and let us know what that is - let the water sit for 24 hours to determine what your 'tap' water normally is.  The LFS can test it if you don't have a pH kit.  They can also test your kH for you.  

Bear in mind that when adding baking soda most fw tanks do not want or need the sodium part. African rift lake tanks are an exception. So it is important to do some big water changes once the cycle is done and before adding fish in order to get the sodium bout of the water.
 
The other thing to remember is that the bacteria use carbonates to as a source of the inorganic carbon they need to process ammonia to nitrate. That means they are using it up. And as it gets used up, KH drops, which will allow the pH to crash more easily with any build up of acids. Since one should minimize water changes during cycling, it is more common to have a pH drop then compared to an established tank in which we replenish a lot of things via weekly water changes.
 

 
To get a tank cycled in a reasonable amount of time, you need to make sure that, in addition to ammonia, the bacteria will also have:

• Lots of oxygen by keeping the surface of your water well agitated to let oxygen in.
• Inorganic carbon (as carbonates) by keeping your KH up. Do not let it drop below 3 dg (55 ppm).
• A good pH level by insuring it is above 6.5. The closer to 8.0 the faster the cycle will go. We do not recommend one alter their pH if it holds fairly steady anywhere between 6.8 - 8.5.
• An optimal temperature by having a heater set to between 75F and 85F. Lower tends to slow the cycle while higher won’t make things go even faster.

from http/www.fishforums.net/index.php?/topic/421488-cycling-your-new-fresh-water-tank-read-this-first/

Cheers folks. I've been given some API ph up, alright to use that?

As I'm still cycling, I'm presuming a pretty much 100% water change is required to continue with the cycle, can't just leave the nitrates til fully cycled?

Thanks again for the continued help!

 

[eaglesaquarium]

PH up is garbage.

You need to add true carbonate, because as TTA said, the bacteria actually will consume the carbonate.

Yes, the water change is best for the continuation of the cycle. The removal of the nitrates is essential at this stage as they are reducing the buffering capacity of the water. The cycle will essentially stop at a pH of that level. And just doing the water change will reset the buffering capacity of the water, so adding the extra carbonate through calcium carbonate or sodium bicarbonate isn't necessary, but you'll need to keep an eye on the pH to make sure that it does drop again, as that would signal the need to do another water change to add some carbonate back to the tank to buffer and allow the bacteria to thrive.

 

[Dave26]

Just emptied the tank as I haven't been home for a couple of days. Refilling it now. Tap water ph is around 6.5. I was buying a new light and other bits earlier and saw some aqualibrium by interpet, a salt with built in ph buffer. Ok to use that to buffer the ph? Fingers crossed the cycle kicks back in nicely! I'll add 3ppm of ammonia tonight and see what happens?

 

[eaglesaquarium]

6.5 is just fine a pH for your fish, depending on the species you decide.  South American fish will absolutely love it. 
 
I'm not a fan of adding anything to the water long term.  As for the cycle, you can cycle it at that pH, but if nitrates go up too high, the buffering capacity will be overcome quickly.  Interestingly, it would be best to NOT use anything to buffer it right now, so that you can get a sense for what that level is.   And then you'd want to make sure that your water change schedule is large and frequent enough to make sure that your nitrates never reach that level.
 
Adding some plants (also appreciated by many South American fish) will help keep the nitrates in check, but only to a certain extent.
 
 
Ultimately, I think I'd just return the chemical, and cycle without it.  If you see the pH start to slip, bump up the kH and pH by adding some baking soda (yes the sodium isn't great, but the last step in the cycle is to do a full water change anyway).  And its best to cycle it close to the same pH as the tank will settle long term.  (Is the 6.5 pH after letting the water sit for 24 hours, or straight from the tap?)

 

[Dave26]

Thanks for your help. Currently waiting for nitrites to drop, but ph seems to have dropped to 6 again, so I'm concerned that the cycle will stall again...

 

[eaglesaquarium]

Either water change, or add some carbonate, as described above.

 

[TwoTankAmin]

 
To raise the KH without raising the GH, add sodium bicarbonate (NaHCO3), commonly known as baking soda. 1/2 teaspoon per 100 Liters raises the KH by about 1 dH. Sodium bicarbonate drives the pH towards an equilibrium value of 8.2.

from http/fins.actwin.com/mirror/begin-chem.html#altering