sps dying

Hi guys! About 5 months ago I upgraded to a 120g peninsula tank, and it's mostly been doing great except the last month or so all my SPS started to really struggle. I had a few acropora frags along with a few encrusting montis, a pocillopora, a povona, and a cyphastrea. The acros are all dead...

out of the new corals i bought a couple weeks ago, i have now lost 3/4 of my tenius, my purple milli, and most of my tort. what could be causing this. my tenius literally had a little white on the base, four hours later half the colony was gone. i saved the top 1/4 of it by immediately...