Hi Claude
This is a pellet type carbon...I suspect it is pH 7 or higher as is safe for reef and cichlid use. I checked it for phosphates and it did not show any trace. pH swing was also small. As a result of that moving rock around I did lose one SPS by STN others were damaged but have recovered.
Water tests to come on Friday/Sat. Here are some comparison photos:
Here is all the images from the day ultra was started;
http://s496.photobucket.com/albums/r...view=slideshow