Added dKH and PO4 zeroed

[Schnizzle]

Can dosing alk drop PO4? Is it appropriate to assume I made the corals happy and they are using the PO4? Both are being measured with Hanna testers that have always matched up with ICP tests.
I started dosing Red Sea KH/Alkalinity to bring my system up to proper levels. I was in the 5’s and brought it up to 7.8 over two and a half weeks.
Apologies is this has already been covered but I’m not finding it.
I was dosing lanthanum chloride to bring my PO4 down from .33 to .05 prior to starting the alk dosing. Every dose of that went exactly as expected. Two weeks ago I tested PO4 at 0.05 so I didn’t dose. This past weekend and again tonight, 0.00 PO4

 

[Gatorpa]

Can dosing alk drop PO4? Is it appropriate to assume I made the corals happy and they are using the PO4? Both are being measured with Hanna testers that have always matched up with ICP tests.
I started dosing Red Sea KH/Alkalinity to bring my system up to proper levels. I was in the 5’s and brought it up to 7.8 over two and a half weeks.
Apologies is this has already been covered but I’m not finding it.
I was dosing lanthanum chloride to bring my PO4 down from .33 to .05 prior to starting the alk dosing. Every dose of that went exactly as expected. Two weeks ago I tested PO4 at 0.05 so I didn’t dose. This past weekend and again tonight, 0.00 PO4

Depending on the test kit the PO4 may or may not have been 0.05.
It may very well have dropped quickly if you brought you DkH up from the 5’s to closer to 8 as you note the corals may be happier and used up the little PO4 you had.

 

[Reef.]

PO4 does fluctuates, and test results are rarely the same even from the same sample, corals use po4, I would think those are more likely the reason for your zero result than dosing alk.