Is my cycle complete?

[jamielynn]

My new 300 gallon tank has been cycling for about 2 months now I’m using plenty of established live rock from a different tank and new live sand. I have consistently been testing no ammonia and no nitrites and nitrates off the charts Although when I dose ammonia to 2 ppm it’s not being converted to 0ppm within 24 hours it’s taking more like 3 or 4 days to be back at 0! My nitrites seem to be converting quickly because I barely get a read in them before they’re back at zero. Should I keep waiting and add some Fritz turbo start 900? I’m so confused because everything is telling me 0 ammonia, 0 nitrites and presence of nitrates means the cycle is complete… if that’s true why isn’t ammonia being processed within 24 hours??

 

[Ron Reefman]

I think you are probably OK. The bacteria that converts ammonia to nitrite may be at a low level due to not having enough ammonia to process.

If I were in your position, I'd just make sure you start developing the livestock very slowly and continue testing until you feel comfortable that the tank is done.

 

[EnterName]

I probably missed something, but these things come to my mind first (in no particular order):

Flow:
Maybe a lack of flow isn't passing enough water through the rocks (where nitrifying bacteria live)?

High Nitrate:
You should get at most 3.65ppm nitrate for every 1ppm ammonia added. If your nitrate levels are "off the charts" there is something messing with the results (possibly nitrite) or the live rock are already introducing quite a large biological load which the bacteria are working with.

Carbon Source:
Have you tested alkalinity? I think nitrifying bacteria use CO2 and bicarbonate as carbon source. Low alkalinity could potentially cause issues.

Trace Elements:
Nitrification relies on enzymes, which are based on iron, molybdenum and I think copper in some cases. It's possible that something is missing. Phosphate could potentially be another limiting factor.

Oxygen:
Do you have a skimmer running? Besides removing detritus it provides a lot of gas exchange. A lack of oxygen would make the oxidation of ammonia difficult and Bacteria growth can deplete oxygen levels quite fast.

 

[Fish Fan]

My new 300 gallon tank has been cycling for about 2 months now I’m using plenty of established live rock from a different tank and new live sand. I have consistently been testing no ammonia and no nitrites and nitrates off the charts Although when I dose ammonia to 2 ppm it’s not being converted to 0ppm within 24 hours it’s taking more like 3 or 4 days to be back at 0! My nitrites seem to be converting quickly because I barely get a read in them before they’re back at zero. Should I keep waiting and add some Fritz turbo start 900? I’m so confused because everything is telling me 0 ammonia, 0 nitrites and presence of nitrates means the cycle is complete… if that’s true why isn’t ammonia being processed within 24 hours??

Welcome to Reef2Reef!

#WelcometoR2R

Let me guess - you're using the API brand ammonia test kit, and after 24 hours it's reading like 0.25 ppm or so, right?

That's a known issue with the API brand ammonia kit, as well as other brands too (Red Sea, for example). I think you're fine.

If you're going from about 2.0 ppm ammonia to about 0.25 ppm in 24 hours on an API test kit, you're cycled

As mentioned above, if there is any nitrite present, that causes an artificial high reading for nitrate, so your nitrate may not actually be "off the chart" if there's any nitrite in the water at the time you test for nitrate.

Good luck!

 

[Fish Fan]

Also, if you used real, wet live rock from a good fish shop, there's no need to cycle, the live rock is already cycled and ready to go on day one, or very close to it

I hope that helps!

 

[jamielynn]

I think you are probably OK. The bacteria that converts ammonia to nitrite may be at a low level due to not having enough ammonia to process.

If I were in your position, I'd just make sure you start developing the livestock very slowly and continue testing until you feel comfortable that

I think you are probably OK. The bacteria that converts ammonia to nitrite may be at a low level due to not having enough ammonia to process.

If I were in your position, I'd just make sure you start developing the livestock very slowly and continue testing until you feel comfortable that the tank

I probably missed something, but these things come to my mind first (in no particular order):

Flow:
Maybe a lack of flow isn't passing enough water through the rocks (where nitrifying bacteria live)?

High Nitrate:
You should get at most 3.65ppm nitrate for every 1ppm ammonia added. If your nitrate levels are "off the charts" there is something messing with the results (possibly nitrite) or the live rock are already introducing quite a large biological load which the bacteria are working with.

Carbon Source:
Have you tested alkalinity? I think nitrifying bacteria use CO2 and bicarbonate as carbon source. Low alkalinity could potentially cause issues.

Trace Elements:
Nitrification relies on enzymes, which are based on iron, molybdenum and I think copper in some cases. It's possible that something is missing. Phosphate could potentially be another limiting factor.

Oxygen:
Do you have a skimmer running? Besides removing detritus it provides a lot of gas exchange. A lack of oxygen would make the oxidation of ammonia difficult and Bacteria growth can deplete oxygen levels quite fast.

Thanks for all the info! I haven’t tested alkalinity I will do that asap and my flow probably isn’t the best for how big the tank is at the moment I’m using two small marineland flow pumps as my EcoTech mp40 wavmakers need a new wet sides and I haven’t been running my skimmer I figured since I don’t have any fish I wouldn’t need it yet but I’ll try running it for a while and see what happens as far as any missing trace elements I’ll have to test for those

 

[jamielynn]

Welcome to Reef2Reef!

#WelcometoR2R

Let me guess - you're using the API brand ammonia test kit, and after 24 hours it's reading like 0.25 ppm or so, right?

That's a known issue with the API brand ammonia kit, as well as other brands too (Red Sea, for example). I think you're fine.

If you're going from about 2.0 ppm ammonia to about 0.25 ppm in 24 hours on an API test kit, you're cycled

As mentioned above, if there is any nitrite present, that causes an artificial high reading for nitrate, so your nitrate may not actually be "off the chart" if there's any nitrite in the water at the time you test for nitrate.

Good luck!

I am using the Red Sea test kit currently reading at 0 ammonia 0 nitrate and what looks like insane amounts of nitrates(darkest purple color) that’s been a pretty consistent result after dosing ammonia and waiting for it to get back to 0 (normally taking about 3 days) my only concern is why is the ammonia not getting back to 0 witching 24 hours

 

[jamielynn]

This was right after I finished aquascaping

 

[Fish Fan]

I am using the Red Sea test kit currently reading at 0 ammonia 0 nitrate and what looks like insane amounts of nitrates(darkest purple color) that’s been a pretty consistent result after dosing ammonia and waiting for it to get back to 0 (normally taking about 3 days) my only concern is why is the ammonia not getting back to 0 witching 24 hours

I think it’s the test kit, I think you’re fine. After two months and with live rock the tank can’t not be cycled. I’d go ahead and add some hardy livestock.

 

[EnterName]

Measuring trace elements would be overkill for a new tank and requires an ICP test. A water change will introduce some trace elements back into the water and reduces the nitrate.

 

[jamielynn]

I think it’s the test kit, I think you’re fine. After two months and with live the tank can’t not be cycled. I’d go ahead and add some hardy livestock.

Thank you! I think you’re right I have been obsessed with this ammonia test I’m kind of a perfectionist lol and wanted to see exact results

 

[jamielynn]

Measuring trace elements would be overkill for a new tank and requires an ICP test. A water change will introduce some trace elements back into the water and reduces the nitrate.

Thank you I’m looking forward to my first water change!

 

[Fish Fan]

Thank you! I think you’re right I have been obsessed with this ammonia test I’m kind of a perfectionist lol and wanted to see exact results

Try not to expect too much precision out of home, hobby-level test kits

 

[Randy Holmes-Farley Verified Community Expert]

Try not to expect too much precision out of home, hobby-level test kits

Agreed. Home test kits and the OP saying she is a perfectionist wanting perfect numbers is not a good combo. lol

 

[exnisstech]

I would just start slowly moving forward. I don't even own an ammonia or nitrite test kit. When I see nitrate present I begin to move forward. I know people like to see ammonia being processed to zero in 24 hrs but my thought is if I'm seeing nitrate I'm processing ammonia. Maybe it's wrong but I've cycled probably 10 tanks or more using this method and never had an issue.

 

[Randy Holmes-Farley Verified Community Expert]

I'd stop dosing ammonia and do a large water change to bring those nitrates down. Since you're consistently seeing 0 ammonia and 0 nitrite, your tank is likely cycled for a normal bioload. Processing 2 ppm in 3–4 days isn't a concern unless you're planning a very heavy initial stocking—just add fish gradually.

I'm assuming it is not accurate. The N for nitrate has to come from somewhere. A handful of 2 ppm ammonia additions would not push nitrate above my target levels, as folks note above..

 

[Freenow54]

My new 300 gallon tank has been cycling for about 2 months now I’m using plenty of established live rock from a different tank and new live sand. I have consistently been testing no ammonia and no nitrites and nitrates off the charts Although when I dose ammonia to 2 ppm it’s not being converted to 0ppm within 24 hours it’s taking more like 3 or 4 days to be back at 0! My nitrites seem to be converting quickly because I barely get a read in them before they’re back at zero. Should I keep waiting and add some Fritz turbo start 900? I’m so confused because everything is telling me 0 ammonia, 0 nitrites and presence of nitrates means the cycle is complete… if that’s true why isn’t ammonia being processed within 24 hours??

Mine acted weird like that but came around I would not add anything but ammonia

 

[Freenow54]

I'd stop dosing ammonia and do a large water change to bring those nitrates down. Since you're consistently seeing 0 ammonia and 0 nitrite, your tank is likely cycled for a normal bioload. Processing 2 ppm in 3–4 days isn't a concern unless you're planning a very heavy initial stocking—just add fish gradually.

Think about it as a percentage if you do a 30% water change you reduce Nitrates by 30 % by theory . So since % of Nitrates is not stated lets say 10 ppm so it would come down to 7 except more will be produced ......

 

[Freenow54]

Thank you I’m looking forward to my first water change!

I was a perfectionist as well. I don't have parasites or diseases , infestations of any kind in the Tank I cycled