Fishless Cycle Help


I need some advice to anyone willing to read and help! I got a 75 gallon tank a little over a week ago with a used filter with filter media in it. I wanted to start my cycle and did so by adding clear ammonia to the tank. At first my ammonia reading was really high 4-8ppm and I tested everything a few days later and I already have nitrites and nitrates in my tank. I did a quick tap water test just to make sure my normal water was without any chemicals.
Here is my question. What do I do now that my tank is reading 0ppm of Ammonia and 2ppm of nitrites and 40 ppm of nitrates. I heard once I have nitrates I am almost done with my cycle so I am continuing to add ammonia to reach 2ppm and see how long it takes to process but I am confused to how quickly nitrates showed up in my tank. Any advice would help!
Thank you


Welcome to Fishlore

Have you run the nitrate test on your tap water? Some folks do find that is where the nitrates are coming from. As to the rest of it. Continue adding ammonia each time it goes back down to zero or very close to zero. Don't add it any more often than 24 hours though.

Once the ammonia you add goes down to zero within 24 hours and you see zero nitrites you will know your cycle is complete.

Well shoot, I didn't read carefully enough and see you have no nitrates in your tap water. Did you keep the original substrate? If so between that and the used (but good) filter media may be why you are seeing nitrates so quickly.


Sounds like your cycle is nearly done! don't add ammonia daily, then see how long it takes to get nitrites to 0. I still advise adding fish pretty slowly after a fishless cycle so you can keep and eye on it for any crashes.

Most photos, videos and links are disabled if you are not logged in.

Log in or register to view

Top Bottom