Question on Brook & Velvet

[MakomekTVN]

All of the fishes died in my friend tank by brooklynella or velvet don't know exact but they all died within a week, all the corals and invert are fine. His leaving that tank fishless for the next 3 months and setting up a new small tank now for fish only. He using some rock and sand from the sump of the infested tank on the new tank. He wash the rock and sand with freshwater thoroughly and soak it in warm rodi water for like 5 hour so my question is are those rock and sand is clean of parasite? Can velvet or brook survive in fresh water that long?

 

[Martini5788]

I would bleach the rocks and sand. Just to be sure. No reason to risk it when all the bacteria are dead anyway from the freshwater. And I would want to be absolutely sure

 

[ThRoewer]

I usually just boil sand and small rocks in a large pot - it's bullet proof.