Problem Adding "Dead" Rock to Reef Aquarium

[chromakey]

Good Day:

I recently added one larger piece of dead rock to my 28 gallon nano reef aquarium and I think I might have made a mistake.

I cooked the rock for about 5 days, adding Seachem Stability to seed the rock. I added it to the aquarium and I had some different things happen. I also added a pouch a Purigen for the first time and treated a few aiptasia with Aiptasia-X the same week.

The macro algae, halimeda turned white and I pulled that all out. The caulerpa also started turning white and I pulled that out. The flower pot coral closed and after I did a water test I noticed a rise in nitrates and that was about it. I have done about 2 - 4 gallon water changes so far.

Do you think the dead rock is leaching out a bunch of phosphates and other stuff? It has been almost two weeks since I added the rock. Should I leave it the tank?

Thanks,
Michael