How to clean rock, add top off and get ready for fish/corals?

[Tochase]

My buddy gave me a tank and came and set it up. He left in the old sand and the (2) clowns, a fire skunk shrimp, and maybe a few crabs?? Also, a couple rock because there are some corals but they look pretty dead to me. He had some algae issues as you can see in my pics that I've been trying to clean up. I have this rock outside the tank that I want to put in, so maybe I need to clean it well. I have taken a wire brush and brushed off all the algae I can. Do I soak it with hydrogen peroxide? Just put it in a trash can with saltwater and a heater for a week or so?

I want to get to the point where I can add some fish and corals sooner than later but want to do it right and realize this may take some patience.

On another topic, my top off water, is it supposed to be saltwater too?

At this point my readings are as follows today:

Salinity 1.023 atc refract
Alk 8.2 hannah
Phosp .38 hannah

6:1 Tetra Stips:
PH 8
Alk 8.0
Nitrate 0.0
Nitirite 5.0

Tetra Test Strip
Ammonia 0

 

[Birdbrains?]

That sounds nice! I am not sure what you wanted with the extra rockwork though, if you want to make sure it doesn't have hitchhikers in it, you can put them in a container and slowly up the salinity, that should make the hitchhikers leave the rock so you can separate stuff that is unwelcome. If you wanna seed it with beneficial bacteria before adding it to the tank, you can put them in a bucket and dump your used tank water from water changes on them but otherwise I will let others advice you more on that

While the water evaporates slightly, the salt remains in the tank, so topping off water needs to be freshwater so you can make sure that salinity remains stable.

You need the nitrites to go away before adding new stuff but that shouldn't take long now at all

It looks to be a good tank, enjoy! (and share lots of pictures lol)