I tested my alkalinity today, (using fastest kit, by Aquarium Systems) The test came out at 3.0 is this safe. Calcium is at 320, I added some reef complete to raise it.
Your alkalinity is way low and your calcium needs to be bumped up as well. Here are levels that you should shoot for 7-10 dkh on alkalinity and 400-420 for calcium.
Some water changes will help... otherwise get a good two part additive such as B-Ionic and does both alkalinity and calcium to bring things up.
We do need to know what unit of measure you're using... like Laddy asked, is it 3.0 dkh or meq/l??