Are these good Reef Rocks to use for my tank? [Pictures inside]

[Rilo]

So I've had these rock in storage for some time. They were bleached and having been sitting for ~1 year since I forgot about them. I'm putting together an aquascape now and was wondering if they'd even be safe to use in my aquarium.

I remember reading that some rock is better for cichlid tanks that's porous and not for reefs? I'm wondering if some of these is that rock. And I also see that some rock sounds and feels more like coral skeleton while some other pieces feel like literal concrete or rock. If that kind of rock would have an effect on anything.

 

[JCTReefer]

I know Substrate such as Seafloor special grade that people use very often for reef tanks is also perfect for African Cichlids. They like a higher Ph like marine organisms. I’d say if the rock is limestone based, calcium carbonate it would be fine to use. I would bleach the old rock before use to get all the organics out of it. About 1 gallon of bleach per 10 gallons of water. Let soak for a few days then add fresh water and dechlorinator. Like prime for example. Make sure all the bleach smell is gone before using. You can also let the rock dry thoroughly after this. Bleach breaks down into mostly salt when it dries. After this you can always put the rocks back in the container to soak and circulate with freshly made saltwater. Use RO/Di to make of course. Then you can test phosphate levels to see if the rock is leaching anything. If so you can dose lanthanum chloride to take care of your PO4.. There’s plenty of details on this forum on how to do both of the above.

 

[JCTReefer]

I used rock that had been sitting dry in storage for years. Was from one of my old tanks. Was a mix of Fiji and Haitian. Just bleached and reused. No issues whatsoever. Man did it leach some phosphate.