Denitrate won't work well in tank, matrix would be better. Denitrate needs a low oxygen environment like a reactor to work best. I just typed a long reply, along with someone else's info in this post for nitrates
How Do I - Best Plant For High Nitrates?
Also ready this sticky after for further explanations.
Review of Nitrate Reducers
I have lots of nitrate ideas, but with the filtration that you are using instant ocean nitrate reducer dosed directly into tank will likely be your best option. Most are good for a canister or large hob, or as briefly mentioned above a reactor. Tag me with any other questions about it after you read the others.
Also, is your other tank still running? You can add some filter material into this one to help your cycle along....
Thanks for the clarification, I was a little confused by that.
You're fine! I'd blame me anyway, since I usually just assume things.Yes, Texas is right. I didn't explain very well.
As the ammonia is processed it creates nitrites. While the nitrite is spiking high and you are doing water changes to keep nitrites down below five it helps to dose the ammonia every other day. More ammonia processed=more nitrites. The ammonia can be fed less often, giving the bacteria a chance to catch up.
It won't prevent a spike, but it will help with the water changes.
sorry for the lack of explanation.
Your cycle might still be there, dose ammonia and see if it processes within 24 hrs, if the ammonia reading stays after then yes, likely you need to restart.
PH- do you have a test for kH? With your pH dropping like that I would be concerned that your kH is too low. KH is a "buffer" that maintains your pH. If it's not high enough your pH will crash. Good thing it happened now vs when fish are inside.