GFO - when to replace?

[SKurj]

I am using bulk GFO, its not like it changes colour when it is exhausted so I don't know if I should be changing it weekly, monthly? I am able to grow macro in the fuge and in the display(not by choice)

I have always run some form of media in the tank for phosphates but never tested for it. I do not have a reactor(or room for one) so I just put bags of GFO and GAC in my hob fuge where the water enters from the tank.

[s_kelley]

I think it says That GFO should be changed out weekly. But I have let it go to weeks With no ill effects.

[CRJ]

well mine says on the box every 6 months. I use antiphos. I change it when i notice algae or do a phosphate test and its above .10 ppm

[downbeach]

I usually know when I see certain corals begin to start turning a little brown, and have to clean the film buildup on the inside of my tank more frequently. After testing its usually around .05 on my Hanna meter, and I replace it then. I use the BRS HC in a reactor, and replace it about every two months.

[kissman]

When i was running GFO I changed it out every 2 weeks.

[Vinny Kreyling]

The only sure way is to test the water exiting the reactor & compare it to the tank itself.
When the #'s get close, time to change media.

[Painted skin]

The only sure way is to test the water exiting the reactor & compare it to the tank itself.
When the #'s get close, time to change media.

+1


They do change color, they get really dark. How often is all depends on the water it's cleaning and how much is used. For me it's around 4-5 months.