Is anyone else having trouble keeping the Aussie Acropora spathulata corals alive long term. They seem to do fine in my tank for 2-4 months, good color, polyps extended and then they suddenly start bleaching from the bottom of the colony or one of the side branches and are gone in a few days. Even if I frag one of branches away from the bleaching area these bleach as well. Tank parameters, Temp 79-81, pH 8.1-8.2, Alk 10, Calcium 360, Magnesium 1450, Nitrate 0, PO4 .02, Lighting 8 hours of 400 watt radiums over a 300 gallon sps tank and 3 Reefbrite LEDs on 12 hours per day. Strong water movement and water changes 20% every month. All other sps are doing fine, growing, and encrusting, some colonies over 7 years old in the tank with them. Would appreciate hearing ideas of what I might be missing and if anyone is keeping them long term?