Historically, leathers were the main thing that responded to aluminum from Phosguard (independent of the discussion of whether it is from particulate or soluble aluminum, leathers were the first responders), and those responded strongly in my tests of soluble aluminum, but not until levels above what most people see when using Marine Pure. The effects may be species dependent even among leathers, but there's almost no useful data on that.
In Jason's tests of a Marine Pure block, one of the main responders was a leather coral:
https://www.reef2reef.com/threads/h...t-leach-lets-guess.247034/page-9#post-2979612
"Effects that were noted after placing in the block:
1. Fiji Leather Coral quickly looked irritated and shrunk
2. Duncan retracted
3. One of my Bubble tips split (otherwise they looked great the entire time)
4. A single drastic short term drop in pH
5. All my sponges "shed" and shrunk
My Fiji Yellow Leather has not had full polyp extension the entire time the block was in place. It took over 2 weeks before it would start looking somewhat ok. The Duncan recovered fairly quickly. The sponges slowly started growing again.
Some of that I believe can be explained by a quick large growth of bacteria in the media (Duncan retracting and quick pH drop). But the longer term effects on the Fiji Leather I believe are more directly related to the Block and the Al content. I still don't know about the sponge if its directly but at least is indirectly related."