Mysterious Coral deaths



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Feb 1, 2021
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Los Angeles
Over the past 3 months I have been losing corals species by species. All colonies of the same species start to show tissue loss within a week of each other in all locations around the tank. So far it has hit all of my Turbinaria and Echinopora These corals have been in this tank for over 5 years and have grown and were well established. Most recently my Acropora have started bleaching from the tips. Has anyone seen this before?

I haven't changed anything on this system for years, however pH has been running on the low side recently (hovering around 8.0).

pH: 8.0
Alkalinity: 3-3.5 mEq/L
Salinity: 32.5 ppt
Ammonia: 0
Nitrate: 10 ppm
Nitrite: .02 ppm
Phosphate: 0
Calcium 440 ppm
Magnesium 1250 ppm

I have a GFO reactor, Carbon reactor and calcium reactor.

Does anyone have any thoughts? I'm assuming it is something water quality related since it is affecting corals all over the tank.

What percentage of blue versus white lighting do you think makes the best coral growth combo?

  • All Blue

    Votes: 18 2.8%
  • Mostly Blue

    Votes: 406 62.1%
  • Even Balance

    Votes: 171 26.1%
  • Mostly White

    Votes: 49 7.5%
  • All White

    Votes: 1 0.2%
  • Other (please explain)

    Votes: 9 1.4%