Nitrogen Cycle Help

[ShadyFish04]

Hey guys, I needed some info on the nitrogen cycle. I am currently on my third week of cycling my 20 gallon freshwater tropical fish tank. I am doing a fishless cycle because I do not want to harm any fish in the process. However, I was wondering if a weekly water change is needed in a fishless cycle? My nitrates are suppose to be below 40 and they have not been going down from 40. On december 7, 2017 my nitrates were at 20. A week later on the 14th of december 2017 they rose to 40. On the 21st when i tested my water again, they remained at a 40. My best guess is to let it take care of itself, but do any of you do water changes to fix this during a fishless cycle?

 

[B-4]

Remember, this is just my understanding of the whole cycle but having higher nitrates is a good sign that the nitrites are being converted. The hardest part of the cycle is waiting for the nitrite conversions. How is your ammonia and nitrite test results? I would want to know their results to be sure that ammonia and nitrites are being converted as you feed the ammonia. Nitrates will increase as the cycle nears an end. You won't need a water change with 40 ppm nitrates unless your cycle has completed. Be sure ammonia and nitrites are 0 24hrs after feeding ammonia. If so, water change to get the nitrates down and add fishies. IMO

 

[ShadyFish04]

The API test i bought only shows results for GH, KH, Nitrates, Nitrites, and pH. My freshwater master test kit is arriving tomorrow so that i can check ammonia and have more clear test results on my water. However, my nitrite level showed as a 3 on the last test i did which was on the 21st of this month.

 

[B-4]

I'd say you are in the middle of a cycle. Ammonia is converting to nitrites some nitrites are converting to nitrates but you aren't done until ammonia and nitrites are 0 a day after you feed ammonia. Your nitrates won't come down in a cycle without a water change but you don't need that yet.

 

[ShadyFish04]

sounds good, thanks for the help

 

[smallfry53]

I don't think doing a pwc is a bad idea. It's been a while since I've cycled a tank, but if I remember right the bacteria can use up buffers in the water and cause the pH to drop which can stall the cycle (or something like that). Testing is the best bet, but without all the info I'd do a 50% pwc, then dose ammonia accordingly and if the nitrite is at 3ppm it will still be at 1.5ppm or so.