When the flow gets slow it's time to go.

[salinity now]

I'm holding a steady 0.09 phosphate in my tank. I'm using 6 tablespoons of GFO in my reactor for 75 gallons. I just open it up full blast and when the flow gets slow I recharge it. GFO is incredible stuff.

 

[bubbgee]

watch your po4 closely when you are under .1 since next thing you know, you'll see bubbles and slime and it'll be a long uphill battle from there.