*I just noticed that monti is under full light, reduce and ramp back up is best, peroxide is a mild oxidizer and so is strong light, ramp it back up or shade that zone a little as intercept.
yes on the bed cleaning or removal its because over time people have figured out sand mainly just catches and holds waste. its atypical for a sandbed below a group of fish to be balanced, so most are removing or just cleaning/replacing them, especially when they're associated with challenges. as long as you don't stir up the waste in contact with fish and corals, nothing can go wrong in the bed removal or replace. Keep sensitives isolated
I would replace sand, it looks nice, and can be occasionally cleaned from here on out to avoid less full takeaparts. *key detail, when you buy the new sand, rinse it under tap, all of it, until its 100% free of silt. then the final rinse in clean distilled or ro water, so that the rebuilt reef isn't back on top of tap.
This is how new beds are made ready. If you dump them in fresh out of the bag, per instructions, it will cloud massively.
fish and shrimp and corals come out first into some bucket or holding container leaving rocks and sand and water only. whatever corals are affixed to rocks remain.
then, rocks are taken apart and detail cleaned, rinsed in saltwater only, then set aside for reuse when the sand is prepped and the greater tank is cleaned out while empty.
you then set the rocks back on perfectly clean new sand, or perfectly rinsed old sand. the rocks have no clouding cuz it was detailed off
then refill w all new water
re acclimate animals, they'll be fine
ramp back production lighting slowly not next day as a final tuning, and, increase the blue levels and decrease the whites as well compared to current settings.
I don't recall the last time we lost an animal in a rip cleaning done truly right with no mixing of clouding and animals. If a cleaner shrimp or some other single organism were to die by accessing an entire reef at once, and then the entire investment's destiny was changed for the positive thereafter Id not call that a fail, though we really don't commonly lose animals during tank cleaning.