also, h202 is not indicated for your issue but we already went 20 pages with that lol, still its fair to point out. The one thing that fixes your whole tank is off the table am aware, and given that choice h202 is a fair thing to try but keep expectations low/ from not doing the certain guaranteed cure which for you is documented 5 pages in our sand replacement thread.
your tank has a zero chance of not looking like the 20 others we collected that had your problems before, but not after, the method well covered. If that peroxide doesn't work while the nutrient sink remains under it, id sure like to see ya get the symptom producers out of that tank but that's hard work agreed. still, its nice to see so many others pull it off so that theres no risk to your tank in the matter, that whole thread was actually built solely for your tank amazingly~
as long as you have a sandbed that when you pick up a handful underwater and drop it a cloud comes, the probs w remain.