Curing LR turned black after soaking in FW
 

Anyone has had this happened? I acquired some rubble LR from a fellow reefer, there are some green algea and mushrooms. As i wanted to make sure there are no pest or hitch hiker. I soaked it in diluted vinegar over night. Then rinse it in fw and let it soaked in fw changing it every 2 weeks and blasting to remove dieing cruds. That was on summer, the green algea disappeared.

Rock was almost brown some where almost white. So i let it soak more, fast forward last week i havent checked it for about 4 weeks since i was busy. I opened the bucket , the water and rocks are black. Blasted with water but rock is still black. It was not really stinky. I guess there are alot of organic matter that decayed or perhaps something else? Im Hesitating to salvage it. Was going to use some of the smooth pieces to mount zoas. Should i bleach it? Just wondering about the blacking part as i have never seen it happen before when I soaked LR

Seems way overkill for hitchhikers and bubble algae. Now everything is dead and rotting. At this point, it might be best to soak it in a strong bleach solution, and then vinegar. Let it dry for a while after that. It will then be dead base rock you'll have to recolonize.

Black often means anaerobic in our hobby. Not good, bleach best option

Bleach
 

+1 on soak it in bleach. 20:1 for a week then freshwater for a week then new freshwater & dechlorinator(prime) for a week. it will be dead & clean. except vermited snails...... somehow they can live through bleach soak. I was surprised.

Good luck

acid bath

Thanks ill try bleach. Im hesitant to use muriatic acid as i do not have a big place to handle the fumes etc...

Just vinegar after the bleach soak will work. An acid is just anything with a pH less than 7 is all. It doesn't need to be extreme. I use so-called "cleaning vinegar" that is twice as potent as regular vinegar. Dilute as you see fit.