need help quick

Hello everybody new here, sorry for the long story, I have a 12g nano reef for 3 yrs with multiple corals , rock wasn't cure when I got it , all kinds of algae outgrew the corals. finally got sick of it, this is what I did and now I really need help, I remove all rocks and scrubbed them out of algae let them sit for a day outside. I replace almost all sand and I replace it with live sand, and now a put the rock back, this is for a fish only tank , siting for 4 days and parameters are up still. Questions is my rock completely death? , is it affecting the biological filtration? my son wants fish soon what can I do
Thanks for any help

 

Hello and Welcome.

Yes the rock no longer has the ability to act as a biological filter now that all the nutrifying bacteria have died.

You may have to seed it with some cured liverock and wait for your existing rock to become colonized again.

 

Some Algae would survive a single day in the sun and so would bacteria, they aren't completely dead unless you used bleach or something when you cleaned them.

you need to wait until your parameters fall, this should teach your son patience(extremely valuable in this hobby).

 

Ok , the live sand I got state it will create the filtration automatically, also I forgot to mention I have some live rock in the back of the tank, also there is a mushroom that survive the scrub, still looks good, at the second day I add a hermit crab still looks ok. sand is turning a little brown is this cyanobactera? is it ok if it is? will wait for parameters to go down , if not I will add some live rock
Thanks

 

That's a marketing gimmick. Add all of your rock or else you will create another cycle.