Couple updates:
Po4 has been steady now right at 0.11ppm. I scaled back the lanthanum dosing bigtime (5ml/day of my solution instead of the 75ml/day). I think my water finally caught up to the po4 being released by substrate, and I've sort of found equilibrium which is great.
Note - I had some lanthanum show up on a Triton ICP test @ .15mg/l. This means that dosing it directly into skimmer, even pretty heavily diluted, still allows some to escape into the water column. I was dosing it pretty heavily, see above, and have since scaled it back - so I will be curious to see the next ICP result.
I lost my Yellow Tang during this time. No other fish have shown any symptoms (Nor was the YT the night before) and all behaving and eating normally. Maybe not related...but given all the anecdotes associated with Lanthanum and Yellow tangs, I figured I'd share as a word to the wise.
No3 is right around 30ppm and has been for many weeks now - I'll probably stop testing this but once every couple of months.
Happy to report the anemones are doing great. The mag hasn't moved in quite a while, and the carpet hasn't claimed any fish - though he did eat a couple shrimp.
Seeing a lot of good growth, pretty happy with how things are going. I'm doing very little to the tank right now - dosing 2 part, a trickle of trace elements and lanthanum, and lots and lots of food!
Some FTS: