A very informative thread. The results are amazing.
You followed the newt method and everything was fine, which caused you to restart the system, what went wrong?
And I noticed that you have enough coarse sand in your display, why was it washed away in one pile? There was no desire to add .... Perhaps a very strong flow, is it so conceived?
What are the parameters now - phosphate, nitrate, KN, pH in the system?