Thanks everyone for helping btw much love !just add it and all is well, you don't even need to test for anything. you're intercepting the point at which the dilution would be challenged, which only had a 5% chance of happening anyway. the small degree of waste in the water will feed those bac and the cycle will work out just fine, easy. you sure can correlate fish behavior to comfort levels, we do it for every other param and it would also include the single most painful, burning parameter they could ever encounter: free ammonia. its not at harmful levels due to dilution, and that bac will catch things up just fine.