I use Oceanic and previously used IO. I switched to Oceanic since IO had a low Ca
reading - 360 range. My corals grew awesome with it though.
Oceanic gives me a Ca
reading of 450-460 I believe. Been awhile since i tested. My tank water always test at 420 Ca
of 2.5-3.0 megs/L. I am seeing more Ca
usage now though so I need to either do more water changes or start dosing. With a low to moderate amount of Ca
using corals, I think Oceanic has worked great fo
me. I have not had to dose anything for about a year.
That is changing now since I have more stonies and a clam. Plus my water changes are not as frequent. I am still on my same bucket of Oceanic though. I have heard mixed results from different batches but seems like IO has as well based on this thread
Always heard good things about Tropic Marin too. I know Steve-S uses Kent. I would try it based on his recommendation alone if it was available. Oceanic, Tropic Marin, IO, and Red Sea is what is available locally for me.