Water cycle

[Compo41]

Hi all

Hope you can help me out been cycling my tank for around 4 weeks its 200ltr with a fluval 306 canister filter I added the recommended amount of JBL Denitrol to kick start it off and this is my results in the picture is this cycled yet or not.
Just need to get this right before adding fish

 

[Essjay]

Have you added any ammonia during the 4 weeks the tank has been running? While the ammonia and nitrite levels look perfect, this is because you haven't added anything which might make them not-perfect. The Denitrol may or may not contain the right species of live bacteria, but the only way to be 100% sure is to test it. The danger is that with no food in the form of added ammonia, the bacteria in the bottle won't have multiplied to make enough bacteria yet.
Unless the tank is heavily planted, I suggest you get some ammonia or Dr Tim's ammonium chloride and add enough to get a reading of 3 ppm half an hour after adding it - this is to allow it to mix in thoroughly. If you use a bottle of ammonia, there is a calculator on here to work out how much to use (the last item) https://www.fishforums.net/aquarium-calculator.htm Test again after 24 hours. If both ammonia and nitrite are zero, the tank is cycled. If one or both are not zero, you need to continue with a fishless cycle https://www.fishforums.net/threads/cycling-your-new-fresh-water-tank-read-this-first.421488/
Make sure that any ammonia is pure - just ammonia or ammonium hydroxide in the ingredients, no perfume, detergent etc.



However, if the tank is heavily planted, and I mean more than just the odd couple of slow growing plants, then as long as the plants are visibly growing, you can add the first batch of fish. To be safe, check ammonia and nitrite every day till you are sure they are staying at zero. After week of zeros, you can get the next batch of fish, and again check those levels every day

 

[Compo41]

Have you added any ammonia during the 4 weeks the tank has been running? While the ammonia and nitrite levels look perfect, this is because you haven't added anything which might make them not-perfect. The Denitrol may or may not contain the right species of live bacteria, but the only way to be 100% sure is to test it. The danger is that with no food in the form of added ammonia, the bacteria in the bottle won't have multiplied to make enough bacteria yet.
Unless the tank is heavily planted, I suggest you get some ammonia or Dr Tim's ammonium chloride and add enough to get a reading of 3 ppm half an hour after adding it - this is to allow it to mix in thoroughly. If you use a bottle of ammonia, there is a calculator on here to work out how much to use (the last item) https://www.fishforums.net/aquarium-calculator.htm Test again after 24 hours. If both ammonia and nitrite are zero, the tank is cycled. If one or both are not zero, you need to continue with a fishless cycle https://www.fishforums.net/threads/cycling-your-new-fresh-water-tank-read-this-first.421488/
Make sure that any ammonia is pure - just ammonia or ammonium hydroxide in the ingredients, no perfume, detergent etc.



However, if the tank is heavily planted, and I mean more than just the odd couple of slow growing plants, then as long as the plants are visibly growing, you can add the first batch of fish. To be safe, check ammonia and nitrite every day till you are sure they are staying at zero. After week of zeros, you can get the next batch of fish, and again check those levels every day

So your saying there is no nitrate bacteria in the tank as yet

 

[Essjay]

I'm suggesting that there is no way to know whether or not you have enough ammonia-eating and nitrite-eating bacteria unless you add ammonia to the tank.
You haven't said that you've added ammonia - if you haven't, after 4 weeks the bacteria you added may have started to go dormant with no food. There may not be enough bacteria for fish if you haven't added ammonia as they need food to multiply.

The only way to know if there are enough bacteria is to test them by adding a dose of ammonia. If the bacteria in the Denitrol can clear that dose to zero ammonia and zero nitrite in 24 hours, then yes the tank is cycled. If they can't clear them to zero, then there are not yet enough bacteria.

The fact that your nitrate is almost zero suggests that you have not added ammonia as cycling makes a fair bit of nitrate.



The only exception is when a tank is heavily planted with fast growing plants. Does your tank have live plants?