Update time...
ATO with kalkwasser has been doing a great job of keeping my calcium and alk up. I've been supplementing two tablespoons of SR kalkwasser powder from Big Al's to every gallon of RO/DI water that I add to my topoff container. Keeping alk steady at around 9.
My monti frags are growing like mad, I'm thrilled with their progress. Red monti cap has been growing more than a cm per week, green cap is slowly crawling up the rock it's glued to and has started to "cup" upwards on one side. I have three setosa frags that started off as one but got broke a couple times as I tried to pick off bubble algae with my fat fingers. Each frag has encrusted to its respective plug or rock and is growing outwards maybe 1cm per month.
Most new acro additions are staying alive... but I have experienced a couple of casualties since October: Red Dragon, Orange Passion, jroovers Suharsanoi, and a tenuis mini colony. One by one they have gone, rather than all at once. The red dragon slowly STNed from the middle after I introduced it, and after trying to save it by chopping it up, all the frags went RTN within a day. The suharsanoi looked good for a good month, polyps out every day, but then I came home from work one day and found it had expelled all its tissue and only a white skeleton remained. The OP experienced a slow STN from the base up, just lost its final polyps last week. The tenuis was already experiencing relatively rapid tissue necrosis when I added it into the tank and only lasted a couple of weeks.
The acros that have survived remain in a steady state, showing neither signs of growth nor sickness. Unless it's normal for shaded tissue to pale? I have noticed that on a couple of frags. I do have one exceptional frag that is visually growing, and that is the aculeus that I got from jroovers! I have noticed that some of the tips towards the top/front of the frag have grown and actually sprouted several new polyps. I'm pretty pleased about that!
Brand new additions that seem to be holding up are a robusta acro from Aaron and a yellow efflo from Ben (Reef Hero). The robusta, I'll be happy if it just survives lol. The efflo I think will do well, it was an off-white when I added it last Thursday and has darkened slightly to more of a yellow as of when I was looking at it last night.
And for my final piece of news.... drum roll.... I gave Aaron the go-ahead to order me a JNS ConeS CO2!!! I will hopefully be installing that into my sump next Saturday

. It should be quite an upgrade - going from an archaic Deltec that pumps out 350 lph of air to a cone shaped skimmer that boasts 720 lph!! And on top of that should be far more quiet

. I'll try to do a picture update next weekend.
While I'm bummed about my losses, they have been moderate... and I mostly understand why, and try to take it all in stride. My tank is still fairly immature, and a little unstable. I read up on reef tanks for months before building, and continue to read articles daily, but it's difficult to put these learnings into practice! My main struggles continue to be nitrates and alk/ca stability. The ATO+kalk has helped with the stability, and I am hoping that eventually the biopellets will help with the nitrates - in addition to the new skimmer. My tank is coming up on it's 1 year mark in a couple months, but the move I performed back in August set me back a little bit. SO I'm not sure where I am on my path to tank maturity, but purple is growing on everything and montis are thriving so I think I'm approaching an environment ideal for acros - which is my end goal. Anyways that's all for now, thanks for reading and happy reefing dudes.