How long does GFO last?

[afboundguy]

I've been researching GFO today and can't seem to get an answer about how long it usually lasts... From what I've read it's a combo of "when I see algae" and around 2ish months as the norm... I know it's dependent on a lot of different things such as bioload, feeding, tank volume etc...

Just wondering if people could chime in when they replace it and about how big their tank is... Thanks!:.

 

[Aquadiva]

I've got a 125... with a 75 sump/refugium. I run both carbon and GFO.. I change about a cup every 2 months... I change carbon every 2-4 weeks depending on how lazy I am.

BTW... I run a calcium reactor... that adds a bit of phosphate to the tank...

 

[pillowfish]

Dave, on my 55g I change out the GFO when I begin to start having PO4 readings over zero-ish It all depends on how much I have fed, water changes or anything else that could possibly effect it(moving rocks around, sand storm, etc...). It also depends IMO the type of GFO you are using and how much water flow you have going through the reactor chamber. JME

 

[Randy Holmes-Farley]

It can be depleted overnight if you start with substantially elevated phosphate.

 

[mgreefer]

Dave, I don’t think you will find a definitive answer of exactly how long it lasts. Every system is different, feeding, bio load, water changes –how often, how much--, etc, etc. Also as Randy indicated, if you start off with a high PO4 level the GFO will be exhausted very quickly.

So your best bet, as Tabitha said, is when you test the water, when you start seeing PO4 rising it means it is time to change. After changing GFO few times you will get a sense of how long on average it lasts in your particular system.

 

[afboundguy]

I've got a 125... with a 75 sump/refugium. I run both carbon and GFO.. I change about a cup every 2 months... I change carbon every 2-4 weeks depending on how lazy I am.

BTW... I run a calcium reactor... that adds a bit of phosphate to the tank...

Thanks...

Dave, on my 55g I change out the GFO when I begin to start having PO4 readings over zero-ish It all depends on how much I have fed, water changes or anything else that could possibly effect it(moving rocks around, sand storm, etc...). It also depends IMO the type of GFO you are using and how much water flow you have going through the reactor chamber. JME

Thanks Tab... I do feed a lot (mainly to the acans ) and I think I do 3-4 cubes every 1-3 days depending on my schedule. I do rinse them out in a strainer with tank water to "try" to help with the phosphates...

It can be depleted overnight if you start with substantially elevated phosphate.

I don't think I have that high of phosphates. I do have a little bit of HA but it is slowely getting less and less now that my skimmer is tuned and broken in plus the macro algae...

Dave, I don’t think you will find a definitive answer of exactly how long it lasts. Every system is different, feeding, bio load, water changes –how often, how much--, etc, etc. Also as Randy indicated, if you start off with a high PO4 level the GFO will be exhausted very quickly.

So your best bet, as Tabitha said, is when you test the water, when you start seeing PO4 rising it means it is time to change. After changing GFO few times you will get a sense of how long on average it lasts in your particular system.

I'm just trying to get a "guestimate" from other peoples systems. My phosphate test kit is only an API as I don't have the money to shell out for the good one so the test when I get a reading might not work. I test "zero" currently but I do have some HA but it's going away so I might be getting a false reading...

I still have a ways to go before I set up a reactor with GFO and Carbon but doesn't hurt to research early Thanks everybody...

 

[pillowfish]

My phosphate test kit is only an API as I don't have the money to shell out for the good one so the test when I get a reading might not work. I test "zero" currently but I do have some HA but it's going away so I might be getting a false reading...

Well ya know Dave...for $5 you can have BRS test your water using the hanna phosphate meter(among other tests..) at the monthly meetings

 

[afboundguy]

Shameless plug tab... Of course if you volunteer to test the water you can test it for free

(mine was a better shameless plug )