sorry I missed that it is gravel, and I just did major pruning, rescaping last week so it got disturbed and cleaned. The amquel can lock up available 02, I dosed all three buckets, instead of dosing the tank before adding the new water. I've never had this happen before cories are back to normal, I've seen all 3 of them
can this affect my benificial bacteria??
can this affect my benificial bacteria??