I would think Darkblade would know what he's talking about...
There are a lot of myths out there. Personally, I haven't had any issues with separating anubias rhyzomes in shrimp tanks. I've done it with my RCS, CRS, and BOTES, no one has had the slightest issue with it. People like to hang on to "excuses", if you will, about why things in their tank are dying.
I believe Prime detoxifies heavy metals like copper. One of the reasons it's the only water treatment I will use.
I agree with the temp. That's about 82 degrees Fahrenheit; my CRS started dying off at around 78 degrees F.