Does GFO expire?

[ezcompany]

I'm using some old gfo currently, and it doesn't seem to be too effective.
Is there a shelf life to gfo?

[HighlandReefer]

As long as you keep GFO in an airtight container without moisture it should last for a very long time.

Keep in mind if your phosphate tank level is high, GFO can become saturated within 24 hrs. So you may need to replace GFO say every three days until your phosphate level reaches undetectable. AT that point, perhaps you can change out GFO every 2 to 4 weeks depending on your food phosphate input. ;)

[bertoni]

I agree that it should be fine in storage. What's the phosphate level in the tank? I agree that GFO can be exhausted very rapidly.