Questions on using GFO in a reactor?

[Dave VG]

How much GFO do you use in your reactor per gallon? And how often do you change it?

 

[teamdulski]

About a gram per gallon, as for how often you change a hanna phosphate test kit would help tell you exactly when, but roughly once a month.

 

[Gravesj1s]

I use about 1/2 cup total on about 70gal tank with 20 gal sump.No testkit,I just sorta use tank glass as a refereence.One of my returns streams along the back glass tends to show a real light greening first,thats usally when I change out gfo.

Guesstimate 4-6 weeks.

 

[pascal32]

see here:

http://www.reefcentral.com/forums/showpost.php?p=17646729&postcount=10

 

[Dave VG]

Blurry thanks very good read. Gravesj1s I like your method for knowing when to change it.

 

[smogl00]

I guess about 4 -6 weeks as well. As for how much, I would use half of whatever the manufacturers suggested usage is for the first time around. I used their suggested amount and shocked the crap out of my tank by removing the phosphates that quickly.

 

[mr.maroonsalty]

I change mine the first week of every month, and use a conservative amount; who knows it could be depleted after 3-4 days. I should get a decent checker, but simply have things higher on the needs list.

 

[naprestsleep]

BRS has a calculator on their site for their GFO. I use around the amount they recommend. Never had an issue when I add too much, I do check with my hannah checker and it says my phosphates are really low but I still use gfo without negative impact on my tank.