New sand is totally prepped and off to the side somewhere. You can sprinkle some of it down into a clear glass of water and the grains simply fall down, no clouding whatsoever in the cup. This matches forty pages from the sand thread, we are set for new substrate now
drain system and catch decent initial water for reuse, you can hold fish and some corals in this water if you like while things are apart. before setting corals in there, swish them off in separate water, detritus will stick to the bottoms and will ride in to the clean water, we want no clouding no detritus to go where your fish are held.
at this point the tank is drained mostly, cloudy at the bottom, but fish are safe in clean tank water and some lone corals too. Those stuck to the rock ride the air. You can mist them with saltwater for half a day if needed they won’t die, rocks will be out of water probably 20 or 30 mins for dentistry and on page one of the sand rinse thread I drained my entire reef with corals for 33 mins in the air in one take on a YouTube video link. You’ll be misting or pouring saltwater on them, piece of cake.
corals and fish safe and clean water, lift out rocks set on a clean counter or a towel. Stacks in the air, the horror
now the tank is mud water and sand, clean it all out totally and set the new sand back in. Wipe the walls down all clean, I use peroxide to clean the insides of scum etc. now the aquarium is clean glass, perfect sand 10000% pre rinsed and no silt for a disappointing cloud.
take a pocket knife and be scraping that algae off, pulling off strands, small cups of saltwater can be poured over the worked sections to carry algae down the sink. First part is dentist and angle tool on plaque (algae) scrape and rasp etc. get as much as you can dislodged, unanchored. Rinsed away. Rocks look clean before any peroxide goes on the former bad spots
*brushing will pestle the algae down into the rock crevices, scraping out and down the sink is best. Whole strands removed
Take peroxide from a new bottle and either dropper it onto the former algae areas or mister bottle spray it, avoiding attached corals. Hit attached rock corals with saltwater to keep them wet as we work. After peroxide burns clean spots for hidden cells a few minutes in the air, rinse off the areas with a little saltwater and set the rocks back in the cleaned tank. Fill up, match salinity and temp to your old systems and fish and corals go back in
dont shine full lights for five days decrease intensity and ramp back up like these are new LED lights. You w have the sand you want, a cloudless skip cycle since all detritus was kept away from sensitives, and this thread will have two very strong efforts logged for others to see
very happy to be able to work with your tank. For this hard two hours work we opt out of waiting till Easter for chems to possibly work, and they’d increase your detritus loading vs remove it, this way is better for longevity even though it seems so offensive.
if you want to try fluconazole or vibrant later on to prevent growback (until coralline covers those zones it will but very slowly) then after the rip clean you can, just not before. It’s going to run clean a good while before any growback, and you can easily drain some water down exposing half the rock no removal needed, hit with peroxide and just fill back up as easy touch ups. A little peroxide in the tank won’t hurt, I don’t see any lysmata shrimp and those are the sensitives but not the rest of what you have
Seabass would want you to see her tank so there’s light at the end of this tunnel

hers was a frag tank easy job.
SeaBass before
SB after, there’s rocks in there!