Hmm... if you're using Reef Crystals, it should be in the 450-480 range if you're mixing it up to 1.025ish. What is the salinity of your freshly made saltwater?
If you're getting 360, you might've gotten a bad bucket (it happens) or your test kit is reading low. Or your salinity is really low. Before you go down the dosing road, I'd get someone else with a different test kit to confirm that calcium number.
Regarding your water change bringing up your calcium levels... if your tank is at 300ppm calcium, even if you do a 50% water change with 360ppm water you're only going to get it up to 330ppm in your tank. So just water changes is not going to get you out of the hole.
If you're really and truly at 300ppm calcium, that could easily explain why your Acros aren't happy. But who knows... those things are picky. That's why I'm an LPS person! If you're at 300 for real, you're going to have to raise the calcium levels up to something around 400ppm, at least, in your main tank. You can do this by mixing up a solution of RO/DI water and a calcium additive like Kent's Turbo Calcium. Slowly raise the calcium levels in your tank no more than 20ppm per day.
After you get it to your target level, stop, and wait a week with no water changes. Then after a week, measure your calcium level. You've now determined how much calcium your tank requires per week. If you started at 400ppm, and ended at 365ppm a week later, you know your tank needs 35ppm calcium per week, or 5ppm per day. Then use one of the online calcium/alk calculators to determine how many ml of 2-part solution you need to use. That's it in a nutshell. A good primer on cal/alk issues can be found here...
http://www.advancedaquarist.com/2002/11/chemistry
...and a good online calculator here...
http://reef.diesyst.com/chemcalc/chem_calc3.html
You don't have to set up a drip using 2-part, unless you're putting in so much that your pH levels go up too much when putting it in all at once. (The alkalinity part of the 2-part solution temporarily raises pH) But I doubt you're there yet. You can just slowly pour the solution in first thing in the morning, when your pH is low. You dribble in some of the part "A" solution, then dribble in the part "B" solution. That's it. Pretty simple.
But I'd double check that calcium reading with a different test kit first. Something doesn't sound right there.