They may melt then, I've had so many melt for "no reason". I've given trying to figure it out. Some are great for years, then over night they take a crap.

Though I've recently starting peroxide dipping my zoas in a 4:1(1cup peroxide, 1/4 cup tank water) peroxide to salt water ratio(let sit 5min), and have had great luck bringing any on the verge of melting back to full glory. Also works great for hair algae growing on the zoas.