Does GFO have an expiry date?
 

Does new GFO have an expiry date?

rust never expires

You need to be more specific with your question.
If you are interested to know the time span for your media's effectiveness to your aquarium water.
most people replace their media between 3 to 6 weeks depending on the quality of the water,amount of algae,intake water from your RO, how much food goes into your tank,amount of fish,how often you do your water changes,...or simply test your water ounce a month and that should let you know for replacement or regeneration of your media.

Well new GFO there are few types of GFO the most common ones are granulated,pellet and High Capacity form.In my opinion they will all do the job (but how accurate and how long do they last) I personally like the High Capacity GFO as it does twice the job than the rest,removes unwanted metals and much more,is regenerateble no loss of media,no muddling,no clumping and by far the cleanest.

Sorry I was basically asking if GFO had a shelf life. I really don't think so because as Fencer saies its basically rust.

LOL rust has a shelf life....ask any ford owner LOL

LMAO

Hhahaaa!!! My guess would be no, it's moist to start though so maybe make sure to keep the lid on?

I'll resurrect this thread. I think the question was not about time in the tank/reactor, but how long can you keep it in the bag (unused) before its potential effectiveness starts to drop?

As long as it stays dry and sealed there should not be an expiry date. IMO it needs to have water cycled through it to activate just like carbon does.

I just used some Barrier Reef GFO media in my tank last month. Its at least 3 years old. It worked well but my phosphates levels creeped back up in about a month. I think the increase is due to the high volume of phosphates in my tank and use of minimal amount of media in a tank with very high levels of phosphates.

So, IMO, it does not have a shelf life as long as it stays dry.