GFO question

I started running GFO 10 days ago. I have about a third a cup running with my carbon in a carbon reactor. I just tested my phosphates and it was almost .5 with the API test kit. How often do I need to changes my GFO?

 

That is a great question with no real great answer! GFO works until it is 100% exhausted. What where you phosphates before starting to use GFO?

Once you start using it you should see a downward trend in phosphates. Have you seen any decrease in phosphates at all?

 

Once your phosphates are below 0.07 ppm you can just rinse a BUNCH of GFO and leave it in there for months. If you use a whole bunch with your po4 at 0.5ppm you will drop the po4 levels so fast that you will probably stress out corals. Its a matter of getting it dialed in. I would get a more precise test kit, and keep an eye on it. As soon as it ticks upward, change your GFO.

 

It hasn't changed much. I changed my ro filter and membrane and it reads zero coming out of there.

 

Can I run GFO and Phosgaard together? I have some phosgarrd I want to use up.

 

No I wouldn't, Phosguard like all Aluminum Silicate absorbents quickly absorb po4 leading to coral stress, and only retains the po4 for 48hrs before it leaches them back into the water. I cannot recommend any aluminum silicate media at all.

 

I would also recommend that once you start the GFO if you ever decide to stop using it or going a different direction that you slowly ween the tank off of GFO.