What's going on with my zoas

[Treehrtsme]

I got a big rock of cheap zoas from a local fish store recently that I'm keeping in my quarantine for now but a chunk of the rock broke off so I put it in one of my tanks to see if my Toby puffer would nip at it. For the most part he's leaving it alone, but they just really don't look like they're thriving. I have been having some trouble maintaining pH but everything else has been all right aside from some algae issues. It's hard to get a clean up crew going on a tank like this. I'm just curious to know this is some sort of disease. The colony in my other tank has some sections that aren't looking great but for the most part it looks fine.

This picture wasn't taken under normal lighting

 

[Derrick0580]

Looks like a sponge is growing amongst them and irritating them.

 

[Treehrtsme]

I do have a sponge in that tank that recently broke off its frag plug but is not very close at all to the zoas. Maybe I picked it up with the rock at the store. Any recommendations as to what I should do? Honestly they look like my leather fingers when they were going out