I have plenty of sponges in my tank. But again, I’m really patient when it comes to starting a tank and will let the rock sit in the tank for a couple weeks while ghost feeding flakes and other foods at night. This draws out crabs, shrimps and other critters, then I go hunting. Once I’ve cleared the tank, everything goes in and enjoy the tank. I’ve done this since the early 90’s with a lot of success.Often wondered what raising the temperature would accomplish as the BB likely survives but not sure sponges might.
Didn’t consider 40ppt but house that affect items such sponges one might want to keep?