phosphorous 180 ppb

Victoria M · Jul 9, 2018

Acid etched dry rock is soaking in a brute container for about 8 weeks. I tested phos & the Hanna ULR phosphorous reading was 180 ppb. Last night I started a little filter running with gfo. I will see how that goes and if it does not drop fast enough I will probably place the rock in the sump where the gfo reactor is. Just a lot of work and I don't want to. lol.
What is the acceptable number I am looking for?
I think this process of soaking and pulling phos might take several to many cycles, is this correct?

And I am so glad I put in the extra time to soak and test the rock. Thank you Randy, BRS, and all you folks for the threads I read. Without you my renewed aquarium would have been an algae factory for sure.

Randy Holmes-Farley · Jul 9, 2018

Many people put lanthanum into the soaking water to quickly and relatively inexpensively precipitate any phosphate that comes off. That greatly speeds the process compared to water changing.

Victoria M · Jul 9, 2018

Randy Holmes-Farley said:
Many people put lanthanum into the soaking water to quickly and relatively inexpensively precipitate any phosphate that comes off. That greatly speeds the process compared to water changing.

Does the precipitate then go to the bottom of the container? Can the phos ever re enter the water column? Also what number am I looking for? I am currently run ing gfo.