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Restarting fishless cycle

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candrews999

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Hi all. I've been doing a fishless cycle for 3 weeks now, initially I dosed too much ammonia so did a 50% water change 2 weeks ago. Ammonia has sat at 2.0 since wc nothing else has changed. I have upped the temp from 28 to 30°c, still nothing. I am considering starting again from scratch but what do I do with my filter media? Start with new stuff or just wash them out under the tap? I'm going to give it another week I think. Any advice gratefully received I really don't want to start again if I can help it.
55litre cube tank
Very soft water
Ph 7.4 ish
Mixture of live and plastic plants

Please help!! [emoji16][emoji16]

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Just a quick query, you mention you have “very soft water” and yet ph is at 7.4.

That ph is not what I would have expected if you do indeed have very soft water.

Can you double check both these please and let us know how you got those figures. I.e from water authority website or from your own test kit (if from own test kit, can you provide what test kit you use, dip stick tests or solution type tests)

Just the fact you say you have very soft water makes me think two things either this very soft water could be a factor in stalling the cycling process, or it could be as you say overdosing on ammonia.

Both of these potential causes have different ways of restarting the cycle really, hence why we should be sure before giving any advice.
 
Just leave your filters running and don't remove the filter media. Make sure the filter is run continuously 24hours a day 7 days a week.

If you have live plants in the tank then have a light, if you don't have live plants in the tank you can turn the light off until you add fish or plants.

Filters can take between 2weeks and 3 months or more to develop. Normally it is around 4-5 weeks in a tropical aquarium. You should see some change in a week or so.
 
Just a quick query, you mention you have “very soft water” and yet ph is at 7.4.

That ph is not what I would have expected if you do indeed have very soft water.

Can you double check both these please and let us know how you got those figures. I.e from water authority website or from your own test kit (if from own test kit, can you provide what test kit you use, dip stick tests or solution type tests)

Just the fact you say you have very soft water makes me think two things either this very soft water could be a factor in stalling the cycling process, or it could be as you say overdosing on ammonia.

Both of these potential causes have different ways of restarting the cycle really, hence why we should be sure before giving any advice.
Hi thanks for replying I got the hardness from the United utilities web site 1.82 Clark degrees. The ph from the tap is 6.8 I believe it is higher in the tank due to the pets at home gravel which is not inert! I have stood a bucket of tap water for 24 hours and that is ph 6.6.
Should I just keep waiting?
The filter is on 24/7 And I have the led lights on for the plants

Thanks again

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There are half a dozen hardness units. Fishkeeping uses two, but deg Clark is not one of them. However , it is easy to covert.
1.82 deg Clark = 1.45 dH (German deg) and 26 ppm, which is indeed very soft.


If you read the fishless cycling method on here http://www.fishforums.net/threads/cycling-your-new-fresh-water-tank-read-this-first.421488/ you will see that one of the things needed to grow bacteria is inorganic carbon - these are carbonates and bicarbonates found in water. Usually (but not always) if general hardness, GH, is low like yours carbonate hardness, KH, will also be low. Unfortunately UK water companies rarely give the KH of tap water (they call it alkalinity).

Having a low KH will not only slow the cycle but puts you at risk of a pH crash once nitrite and nitrate start to appear - and that will also stall a cycle.

You could try doing another water change, and redose ammonia to 3 ppm afterwards. Or something that worked for me though most people to not recommend it - add bicarbonate of soda, the stuff used in cooking. You may already have some in the kitchen, and if not it comes in small tubs in the home baking aisle of the supermarket. For the volume of your tank, add 2 x 5ml spoonfuls to some water then pour into the tank. At the end of the cycle, you must do a 100% water change to remove all the bicarb before getting fish.




Can I ask, the pH of 7.4ish that you gave, is that the tank's pH or freshly run tap water? Freshly run tap water often has a pH different from water that has been allowed to stand.
While it is more likely to have low pH with soft water it is not impossible to have a higher pH - I have GH 5 and pH 7.5, so my pH is similar though my hardness is higher than yours.
 
their pH is slightly acid (6.6) 24 hours out of the tap and is being buffered in the tank by the substrate.
low kh doesn't affect the bacteria.
 
Ok, sound like you have soft water.

1.82 Clark (or English degree) is around 26ppm of hardness.

Quoted from the fish less cycle article -

“The ammonia converting bacteria do not function as well the lower the pH gets. If your pH drops under 7.0, they start to slow their activity markedly and under 6.5, they slow dramatically and by about 6.0 they will appear to stop completely.

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 (24C and 29C). Lower tends to slow the cycle while higher won’t make things go even faster.”

So at this stage I’d recommend doing a large water change, this basically resets the ammonia back to near zero and then redosing the tank back to 3ppm ammonia, no higher.

The low kh, if indeed you have low kh, this will need to be confirmed but could be the cause of the stall of the cycle, so you could simply put in the filter or tank a mesh bag of inorganic carbon which could be crushed shell / coral, this would help raise the kh temporarily until the cycle is completed then simply take bag out once done.
 
low kh doesn't affect the bacteria.

It does; the nitrification process uses up carbonates and if there aren't enough carbonates in the water, the cycle will stall.
 
Thanks for the advice everyone, so I need to do a large water change and add some carbonates temporarily until the cycle completes as well as dosing ammonia back to 3?????

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First of all apologies for missing the info on the pH of water that had been allowed to stand :oops:


The fishless cycling method on here (see the link in post #6) was designed so that nitrite can never get so high it stalls the cycle. It recommends adding 3 ppm ammonia at the start of the cycle, then only adding more ammonia when certain specific targets are reached.
 
First of all apologies for missing the info on the pH of water that had been allowed to stand :oops:


The fishless cycling method on here (see the link in post #6) was designed so that nitrite can never get so high it stalls the cycle. It recommends adding 3 ppm ammonia at the start of the cycle, then only adding more ammonia when certain specific targets are reached.
No problem I'll do a large water change and add some sodium bicarb/shells and add ammonia to 3.0ppm??

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When you've done the water change, wait half an hour for the new water to mix in then test ammonia. You don't need to add a 3 ppm dose, just enough to raise the reading from whatever it is after the water change up to 3 ppm.
 
When you've done the water change, wait half an hour for the new water to mix in then test ammonia. You don't need to add a 3 ppm dose, just enough to raise the reading from whatever it is after the water change up to 3 ppm.
Ok will do and some sodium bicarb too??

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With a tank pH below 7, items made of calcium carbonate should do the trick. This means coral - whole or crushed - limestone/tufa rock and even shells. With a 55 litre tank you probably don't have an external filter, and those are the best place to put a bag of crushed coral, so perhaps a chunk of limestone or tufa, or even a piece of coral. I would only use bicarb as a last resort.


Do you intend having live plants in the tank?
 

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