Phosphate rx

[fishboy2021]

So I brought out my phosphate rx and decided to dose a small amount, 2 drops for my 20g tank. My acros and pectinia start to slime up does anyone know what’s happening?

 

[Pistondog]

Concentrated lanthanum chloride.
It produces a fine flocculant when binding phosphate.
I would dose that diluted 100:1 with rodi, dripped over 5 hours into a 5 micron sock. With a skimmer running.
Keep the flocculant concentration low enough not to bother anybody.

 

[Walt1980]

I used phosphate rx last night and found my starfish dead this morning, I’ve read somewhere about it before, anyone knows reason?