GFO/Reactor amount advice

[wright4941]

I just got my BRS GFO reactor and wanted some feedback on what would be a good starting amount of GFO to put in. My tank is 90 G, my sump in 29. I roughly have around 100 pounds of live rock. My phosphate level has been running about .25 or so based on API phosphate test, so who knows how truly accurate that is. All I know is that Ive been combating a cyano problem so more than likely Ive got phosphate issues right??

The BRS phosphate calculator suggests using 1.25 cups of phosphate to start. However, Im concerned about shocking the system and adversely effecting my corals. Im thinking cutting that at least in half might be a good place too start, but wanted your guys opinion about this.

Thanks for the help.

[anderson0196]

I used the BRS recommendation which is supposed to be a starting point....I saw a drop to 0 in 4 days....nothing in my tank yet other than hitchhikers so not a big deal, but I would dial it down a bit if you're looking for a gradual reduction.

[ddefilippis]

i am doing the same thing - i just got my brs reactor and will run gfo in the bottom and rox on top. I am going to ramp it up to the brs recommended amoount over three months, but will likely stop adding gfo when my phosphates hit zero.

[scarface70706]

i just put in 1 1/2 cups of gfo in my 90 gallon system (total of 115 with sump). this was the first time i ever ran gfo and so far so good. i dont think the amount of gfo im running will shock my tank.