[shrimpchips]

On the profilux, are you dosing once a day or a total of that volume throughout the day?

Also, how full is your tank of coral? When my nano was full of SPS, it would drop 20 ppm Ca and 1 dKh Alk a day without dosing - likely your dosing regime just isn't cutting it.

Also, Alk of 7 dkH is fine. I keep my alk at 7 - 8 dkh (Fauna Marin supplements on a Profilux doser). I think I'm at about 256 ml (16 x 16ml) of alk a day, and 272 ml (16 x 17 ml) for Ca a day in a 100g + 30g sump (~115g total). Mg I'm using like crazy, but that's a different story.

My SG stays at 1.026, and I do a single 5g water change every week (or two).

If you're not already, I'd break up your doses to be more frequent and dose more in total. Try to test every day for a week to dial it in. Your Mg looks fine, and your SG isn't much of an issue.

To bring everything up, you may want to dose heavily for 2 weeks, then taper it off to a maintenance level. Slowly trying to raise your Ca will take weeks. Alk you probably want to do slower to avoid Alk burn, but Ca you can move a lot faster to bring it up to the 400 - 440 ppm range.