Yes she said she would. test number 4 underway.
test is .00ppm. Im going to have her test it every hour and write down the readings.
from the sounds of things I suspect you had a mini cycle..
or something died and is stuck somewhere. the source showed 0 so pink is right..it is definitely something in the tank.
btw,, bored again..never.. I mean never clean everything in an established tank.at least not at once.. even a 100% water change will not reduce the bacteria count by much.
however, cleaning the tank walls, subtrates , ornaments etc..will have a significant impact on them..the bacteria will cling to any and nearly all surfaces in a tank.
while most of the bacteria (or a significant number) reside in the filter..cleaning everythong to make it sparkly clean may send your tank into a mini cycle.
I suspect in this case the change out of the substrate may have had an impact on the bacteria..especially if you had much suspended pariculate in the water column..this could ultimately cover the filter media and could sufffocate the bacteria..sending it into a mini cycle.
with that said.you have other tanks running..transefer some of the bacteria into the tank that is suffering..(squeeze a sponge, or other filter media) into the other tanks filter.
this will jump start the bacteria that is MIA.
monitoring the water is the best way to see if the bacteria have recovered.