I am using Oceanic and am almost done with a 200 gal bucket. The ease of mixing is nice, and the raised Ca is a plus in my eyes.
I am using it in my 90 gal reef and my 45 gal seahorse tank.
The problem I'm having is in keeping the Alk up. Freshly mixed it seems to be around 7. I buffer it up with part 2 ofrecipe1 of Randy's 2 part to get it to 12. The Ca is good, the PH is then a little high (8.4ish). Then do my water changes with it. In the system I have to add about 100 ml of part 2 and 50-60 ml of part 1 daily to keep the Alk at 11-12 and the Ca at 450-480. If I miss a day the Ca still tests good but the Alk will dive to 7-8.
This seems extreme to me and is a problem that I didn't encounter with IO or Reef Crystals. Not to mention the Alk & PH fluctuation just in a 24 hr period between administering the additives. This constant slight swing has put a strain on my corals as they don't seem to be thriving as they once were.
As for the algea/slime thing my sand bed almost pulses with color

, from pure white for a few days to redish brown for a few days and back again. This happens in both tanks. It can be explained as having to much of a bio load in my reef as I am heavy on the fish side. But My seahorse tank hardly has a HUGE load with 3 feeding station trained erectus, some snails, and a few peppermint shrimp. This wasn't occurring with the other salts but it isn't a major issue now as it is so slight.
All in all I think I will go back to IO. Supplementing Ca when mixing new salt is a small price to pay to have my alk and PH stable again.
Kevin