Interesting, first I’m hearing about this. I’ll search it . My experience with Marco has been the opposite. I’m not even a dry rock fan, but I have added Marco rock structures from Chandler rocks to 2 systems (also containing Australian live rock) and they have become freckled with Coraline in 7 weeks and look natural in a few months. The acros and ICP tests have all been on point, so it’s not leeching anything. I’ll try putting an encrusting Monti on it, which I never do, just to see if it encrusts the rock lol.
With these hello reef kits, I was given one for my son back in December. The kit is missing a lot of necessary stuff so it was an added expense of a gift lol. The Carib sea rock that came with it was very dense. Like purple painted lead lol. The thing that I found odd is when I was drilling the rock, it was more like I was drilling into a resin rather than natural rock. Not sure where they source their rock, or if it’s synthetic, but it was dense bricks with no porosity, the attributes which make rock poor quality.
Another thing to think about.
I ordered a live Marco rock package last summer, which is essentially dry macro in the ocean for a few years, and it came in loaded with life. Not sure where guys aren’t getting ocean life on it. Something is suspect there.