Tank Crash?

[chadwick23]

Hi All,

I have recently had an issue where all of my corals except 3 died off (11 died off). The ones that died off are some zoas, acans, hammer, frogspawn, Kryptonite Candy Cane, and favia. I have two clownfish and a six line wrasse. I'm wondering if I had some sort of tank crash but from all the testing, everything looks fine. The tank has been set up for a little over a year now. Im running an AI 16hd light over a nuvo int 50 cube, 24x24x20. Off of the main tank I have it draining into the sump that goes into a filter sock. I'm running a SCA-301 proteins skimmer, marine pure bioballs, chaeto algae, dosing red sea Cal/Alk/Mg. I have about an inch sand bed with about 50ish pounds of rock. I'm running an nero3 in the display tank. Water change every two weekish. All the corals died within a few days of me seeing a visible issue. Some did have a little life left in them and I'm hoping they bounce back. I started auto dosing around 3 to 4 months ago testing once a week for Cal/Alk/Mg to make sure what I was dosing is correct. I was checking Alk every 3 days. After the "crash" I ran some test that I had at home and sent in an ICP test.

Salinity 1.027
ULR Phosphate .02
Alk 8.4 dkh
Mg 1480
Ca 520
Nitrate 1.49 ppm

I've uploaded pictures of the icp test

Thanks for any input and let me know if I need to provide any more info

 

[Spare time]

Add aminos, vitachem marine, or feed more. That nitrate may be 0. Alternatively, run the skimmer so it won't collect anything or on a timer (i.e. on at night). Phosphate is also possibly 0. That's my main guess

 

[Cristy17]

My 2 cents..the nitrates are too low. I have been following the recommendation of at least 4 and if it goes lower, you have to dose nitrate. As you can see, nitrate is an element ICP does not test for. Sorry to hear about your reef crash.