My rock wasn't fully submerged. The second batch should be much different than the first. Lots of sponges, stars, colors. Mine came in August. Not sure about march. I would still have it posted as a standby. Its quiet expensive to use TBS. The second batch will be the money batch. I would definitely lose some of the base rock and keep the 2and batch coming. You can store it in buckets and some cirulation or trade it with your LFS. I would be all over my installer to get my salt mix station hooked up. You are doing it the hard way. You can always glad 2 brute trashcans and mix a much larger amount at a time