Need advice guys I have 40g tank over year old , had few sps, hammers, torce and other stoney corals , I put them with my other soft corals like lots of johas, gsp, keintree gonipora few mushrooms and other soft corals ,, one by one all my Stoney corals died but where all my soft corals thrives,,, what is reason dying my Stoney corals I used to change water every week and all my perimeters were within range So please pro guys what could be the reason not having lack with Stoney corals !!