Trident. Now that is cheating.I use a Trident but still test weekly, I’ve never seen it dive like that in a day
So the LC is by now bound up and gone. I understand that it binds with PO4 and becomes kinda inert. (Might not be the proper scientific definition). Just caught up in skimmer or socks or sump as a grit.
So if the ALK consumption period extends beyond -- I don't know -- 24 hours or so then it is likely coral uptake.
Might be a question for Randy over in the chemistry forum. I believe he has written some stuff on lanthanum IIRC.