Regenerated gfo looks rusty- bad?

[Cory]

I've regenerated this rowaphos about 3 times this time it really looks rusty instead of blackish. Is it bad?

 

[Randy Holmes-Farley Verified Community Expert]

I wouldn't worry too much about the color.

 

[Cory]

Thanks I'll use it. Would you think that the gfo is ready to be used when the po4 in lye water reaches 0?

 

[Randy Holmes-Farley Verified Community Expert]

That seems reasonable, assuming you test method works in such a solution.

 

[Cory]

Yes what I do is acidify the water a bit. Can I use vinegar to bring the ph down, or will that interfere with salifert po4 test?

 

[Triggreef]

How are you regenerating GFO? I'm Very interested I go through ridiculous amounts.

 

[Cory]

Just add some lye, pure lye, to the water (pure). Gfo releases po4 then you start the batch again with fresh water and lye until po4 reaches 0 or low. The po3 will reach off the charts! I let mine soak in lye water for a day or a few hours between changes. 25$ for a huge bottle of lye.

About 1tbls lye per gallon iirc.

 

[Randy Holmes-Farley Verified Community Expert]

I don't believe vinegar will impact it, but it may only have a certain range of pH and alkalinity that it works for.

 

[Cory]

Hmm. So if I acidify to ph 8ish then all is good? I can use my ph probe from the apex but that might mess with the probe?

 

[Randy Holmes-Farley Verified Community Expert]

It still won't be the same as seawater, even at pH 8, but it it probably close enough.