Time to change GFO?

[Blind45503]

Hi everyone! So I've been battling at gha outbreak and finally started run GFO for almost a week now my phosphates seem to be rising the last two times I tested is it possible the gfo is depleted already? I've looked online and it seems people have varying opinions on when to change it, some say once a month some every two months some say in the beginning every 4 days? Any input would be appreciated!

[thegrun]

Only testing for phosphates will give you the answer. When the phosphates start to rise it is time to change the GFO.

[Blind45503]

Thanks for the quick reply, looks like its time to change it then. Will it start to last longer once the phosphates get under control?

[bromdad]

Depends on the size of your tank, the phosphate level, the amount of gfo in your reactor (highly recommended). First start by measuring the PO4 in the reactor effluent. If it is zero then no need to replace it. If it is elevated then slow the flow and recheck a bit later. If still elevated than replace or recharge it. At any rate if you have a reactor, when you first start make sure the effluent has zero PO4. As soon as it goes up. you need to replace or recharge it. If you have had a phosphate problem for some time, it may be in your rocks and that is a different story. As long as you have the correct amount of GFO and proper size reactor for your tank and proper flow and the effluent reads zero you should eventually bring the problem under control. Good luck!

[Blind45503]

Thanks that was actually really helpful! Im gonna go test it now.

[MrTuskfish]

GFO also eats silicates and they play a part in how long the GFO lasts.