SPS and LPS browning / dying off - did extensive water test, looking to see if you spot anything bad

[Eryeal]

So long story short, have a relatively new tank that's about 8 months old. Softies have always been hit and miss - some do great and multiply like crazy, others melt off. Probably 50/50. Had some encrusting montis for a few months that did really well - nice color and growing. Had some acro that didn't really grow or color up, but kinda put that in the "to be expected" category with such a newish tank. Had some torches that took to the tank really well, too.

A few weeks ago, a lot of the SPS corals started turning brown. Montis and acros. I also started losing torches one-by-one as well (would just retract for a day or two, then start to melt away, not sure if related). My really nice encrusting montis that were doing so well, growing and bright, lost all their color and browned up. Some took longer than others to brown, but eventually it happened to just about all the montis and acros. Zoas pretty much stayed the same.

Basic tank parameters have been pretty steady (keep alk around 8.5, calcium around 420, mag around 1300, 1.024 salinity, temp 78, lights schedule the same, 10-15% WC biweekly, etc). Keep in mind that many of the corals, especially the montis, thrived for several months until the above started happening. So got a full water test done, and just posting the results here to see if anything sticks out as potentially really bad, in an effort to rule out something in the water? Thanks in advance for having a look - I really don't know about a lot of these:

Aluminum

Antimony

Arsenic

Barium

Beryllium

Bismuth

Boron

Bromine

Cadmium

Calcium

Cerium

Cesium

Chlorine Total

Chromium

Cobalt

Copper

Dysprosium

Erbium

Europium

Gadolinium

Gallium

Germanium

Gold

Hafnium

Holmium

Indium

Iodine

Iridium

Iron

Lanthanum

Lead

Lithium

Lutetium

Magnesium

Manganese

Mercury

Molybdenum

Neodymium

Nickel

Niobium

Palladium

Phosphorous

Platinum

Potassium

Praseodymium

Rhenium

Rhodium

Rubidium

Ruthenium

Samarium

Scandium

Selenium

Silicon

Silver

Sodium

Strontium

Sulfur

Tantalum

Terbium

Thallium

Thorium

Thulium

Tin

Titanium

Tungsten

Uranium

Vanadium

Ytterbium

Yttrium

Zinc

Zirconium

0.018​

0​

0.006​

0.007​

0​

0.002​

3.066​

46.774​

0​

420.121​

0.11​

0​

17030.9​

0.001​

0​

0.002​

0​

0​

0​

0​

0.009​

0​

0​

0​

0​

0.018​

0.075​

0​

0​

0.003​

0.003​

0.471​

0​

1136.74​

0​

0​

0.012​

0.005​

0.002​

0.041​

0.009​

0.028​

0​

359.236​

0​

0.004​

0.009​

0​

0​

0​

0​

0​

0.167​

0.005​

9207.96​

5.1​

890.218​

0​

0.001​

0​

0.004​

0.001​

0​

0​

0​

0​

2.687​

0​

0.002​

0.004​

0​

Orthophosphate

Ammonia

Nitrite

Nitrate

Alkalinity

Cyanide

Chromium

Chloride

Silica

Sulfate

0.022​

0​

0.0246​

3.162​

8.4​

0​

0.001​

17030.9​

0.358​

2665.31​

 

[BiGGiePauls33]

Po4 and no3 look low. I tend to keep mine .05-.10 and nitrate 5-10

 

[Eryeal]

Po4 and no3 look low. I tend to keep mine .05-.10 and nitrate 5-10

Thanks for the feedback. I don't believe that those can be the cause if they've been kept at the same levels consistently, and many of the coral (especially montis) have had great coloration and growth, and then just suddenly go brown in the span of 3 weeks. Since it's affecting a majority of the tank at pretty much the exact same time, I think it needs to be something different. Being on the low end of those may stunt growth, and/or result in not coloring up that well .. but wouldn't cause almost an entire coral tank crash in a short period of time I don't think?