Due for an update! If you don't want to read the whole post, basically my Nitrates went to zero and I starved my corals. Now things are trending in the right direction again.
I went through a rough couple weeks to start March. In short I believe the issue was my Nitrates bottomed out (because I have no idea what else it could have been). In a matter of a week nearly all of my sps corals turned brown, lost all polyp extension, gonis closed and over tank looked like crap. Ironically I sent in an ICP test (attached) on 2/20 (before I knew I had an issues) and everything was on point besides iodine a little low.
2/20 - Sent ICP and results came back looking good
2/23 - Corals looked meh (polyp extension not great, could tell something was off)
2/24 - Didn't want to panic so ran tests and let it sit for a day to see if it would bounce back (N-0, PO4-.04, ALK-8.8, CA-426, MG-1370, PH-8.03)
2/25 - Tank looking worse so when in doubt do a WC ( 40% change, and changed out the carbon in the reactor)
2/26 - Tank looks even worse!
2/27 - Buy Neonitro and dose 45ml over the course of the day (Nitrates rise to 5)
3/1-3/7 - Keep dosing nitrate and feeding the tank like crazy with reef roids and other foods, turn off filter roller, skimmer, carbon reactor and reduce fuge light period.
3/8-3/15 - Corals coming back to life. Currently lost 2 acros. 1 acros and 1 goni not looking great. Many corals not with great color yet, but coming back and have PE again.
I know the 0 nitrates in the beginning should have been a red flag, but my tank has ALWAYS had near undetectable nutrients. I have always depended on using the Aquaforest supplements to feed the coral, and for while had a lot of success with that. I think that the issue was I never increased the dosing of the coral foods. I increased my 2 part to match my alk/ca/mg demand, but that was it. As my frags grew to colonies, they required more food and I was not providing enough which cause the tipping point and they starved.
In the past my first reaction to anything being off in the tank has been, when in doubt do a water change! In this case I think the large wc and the new carbon only made the problem worse, driving down nutrients even more.
I have now increased my feeding significantly and will be monitoring nutrients more closely. All my filtration is back on online as well. I think the fuge and skimmer offline decreased my average PH by about .15.
During the week when my tank was on the downward trend I test for stray voltage, tested my RO and salt water tanks, re calibrated my refractometer, ordered secondary test kits, etc.. Tried to cross anything off the list I could think of. And no had not made any changes to lights or other settings on the tank. Below are a few pics of my tank from January and comparison to the week from hell.