Nitrate cycling question

[Fish noob]

After a month, my tank finally cycled. I did a large water change (about 90%) because by nitrates were through the roof.

After the large water change, they are still extremely high. Around 120ppm

What should I do to drop the nitrates because the water change didn't seem to do much. Should I do more changes?

I have a 30g rimless JBJ all-in-one.

 

[apet66]

Definitely do another water change. Nitrate needs to be less than 20.

 

[Fish noob]

Definitely do another water change. Nitrate needs to be less than 20.

Can I do it immediately? Or do I need to wait a certain length of time since I just did one today?

 

[apet66]

It won't hurt to do it immediately. All your bb is in the substrate, rock and filter media if your running a filter.