ARE YOU RUNNING GFO 24/7?

BRS

Do You Run GFO (Granular Ferric Oxide) 24/7?

  • I Run GFO 24/7

  • I Run GFO Intermittently

  • I Run GFO only when necessary

  • I Never Run GFO

  • What is GFO?


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mattdg

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Please share here your preferred method, when it comes to using GFO (Granular Ferric Oxide) . Do you run 24/7, intermittently or never? Leave some details about your system (age of your reef, size of your tank, type of coral, what reactor you run, what you feed, substrate or none) and reason for running GFO, the way you do.

My tank is a 4 year old 120 gallon, SPS heavy, mixed reef and it seems to do best running 3/4 cup of regular GFO 24/7 (not high capacity) in a reactor, swapped out once a month. It keeps my PO4 level right where I like it. This may have something to do with the 2" aragonite substrate. It does get stirred and maintained. Visually it is what works for me and I personally prefer to have some phosphate in the water to reduce with the GFO, rather than having to add something to increase the PO4 levels. I am not a heavy feeder, using mainly aquanix cool green flakes and nori, which are both also a source of at least some phosphate. All said, I am happy with how this system is dialed in and have no plans to change anything, but am curious about how others are managing GFO usage.
 
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Pico bam

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I rarely used gfo I keep liquid phosphate remover handy If needed witch is much more effective imo and cheaper. Lately my corals have been sucking up so much nutrients I’ve had to dose po4 and no3 a couple times. I never really understood why people would shell out and keep a reactor of the stuff.
 

Biglew11

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how stocked is your tank?
Do you use some other method to keep phosphates low like a macro algae?
Very lightly stocked at this time. Two clownfish, 1 coral beauty, 1 Tommini tang. Tank is 75 gallons.

I have some ulva in my sump. Nitrates are kinda high around 40 ppm. Other than the ulva I'm not doing anything to keep phosphates down. I do know that when my phosphates drop my nitrates start to increase.
 
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mattdg

mattdg

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I know a lot of people have a difficult time maintaining PO4 levels, especially those running bare bottom systems with little to no live rock. I have a similar issue in my 100 gallon frag system, which is mainly egg crate, coral racks and glass. For those of you who measure low to no free PO4, I totally understand not giving GFO a second thought.

Wondering if anyone else with a fully established system has to run a little GFO, as I do. Or even those of you with reefs under a year. How are you using GFO, in your system?
 

Uncle99

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I run phosphate at .15ppm max.
I use GFO (Rowa) when it reaches .2ppm, but only down to .1ppm, then it gets pulled.

Otherwise it would zero out my phosphate in time, and for my system, that would have bad consequences (Dino’s).
 

Lost in the Sauce

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220g system volume running a 3cf refugium with a Heavy bioload. I run two reactors 24/7 with 3 cups each. Flow is raised or lowered through the reactors if needed, but generally stays very consistent until the GFO is exhausted.
 

Keen4

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I had over dosed on po4 with some powder when I was a newbie. So my po4 was super high. Hard to find those HR test kits. Hanna was the best and had to order online. But I got my po4 down to 1 from way above 10 within a month. My system is thriving. Just started a GFO reactor. Forget the name. But after reading this thread I may need to rethink zeroing out my PO4. I have a mixed reef. Lots of invasive bubble tips. Tangs clowns, betta, Zoas, euphilia’s…
 

Keen4

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I had over dosed on po4 with some powder when I was a newbie. So my po4 was super high. Hard to find those HR test kits. Hanna was the best and had to order online. But I got my po4 down to 1 from way above 10 within a month. My system is thriving. Just started a GFO reactor. Forget the name. But after reading this thread I may need to rethink zeroing out my PO4. I have a mixed reef. Lots of invasive bubble tips. Tangs clowns, betta, Zoas, euphilia’s…
 

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xCry0x

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I just spun up a reactor with a minimal amount of gfo after using flucanazol to nuke a growing gha mess in my tank. (Tank has been running for 6 years, something got out of wack and gha started going nuts).

I assumed I'd see a big nutrient spike, so prempted with the gfo.

Now I have cyano starting with 0.0 nitrate and 0.04 p04 two weeks after they last off the GHA left.

So I pulled the GFO today.

My first nano always had gfo running, but I also never tested anything, rarely did water changes, and everything grew like crazy so .. lol.
 

lost66

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I believe GFO was a cause of a year long war with dino. And then I wasn't using it, or any other phosphate remover for more than a year and tank was super happy. Now I am a week after another apocalypse (cyano + briopsis) and my phosphates raise super fast and I am forced to use GFO again.
I have 240g tank, i use 1/3 cap of that concentrated BRS version. It is half of recommended initial dose. I run it 24/7. But I hope when my refugium rebuilt in time I will shut down GFO. I believe it is a ticking bomb and necessary evil.
 

Miami Reef

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I haven’t had the need for GFO these past weeks. I’ve actually been needing to dose phosphates!

If phosphates were to ever get too high, I wouldn’t hesitate on using some GFO. I haven’t had any bad experience with it, and it works very well (use much less than what you think you need). It works really quick IME.

Using about a quarter cup could easily strip it phosphates in my 260 gallon to 0.00ppm (high capacity GFO). It might be due to the relatively small amount of rock work I have.
 

LeftyReefer

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Gfo is for lowering phosphates.
ah haha oops. proof I've never used GFO. haha

My phosphates stay pretty stable too. They stay pretty much pegged at .03 or .04 ppm. The highest reading I've ever seen in my tank was .07, back when the tank was still pretty new. I haven't seen a reading higher than .04 ppm in probably a year.
 

Waters

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I have found a perfect balance in my BB one year old tank where my phosphates sit between .07-1 and my nitrates sit at about 6 without running any GFO. All of my previous tanks I had to run it 24X7. Only difference in this tank is the BB.
 

mtraylor

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I used to run it 24/7 on my tank to keep phosphates at 0.05 to 0.1 in mixed reef with real-life rock. Heavy feeding the tank. Best used in biochurn reactor using high capacity from brs.
Also had refugium full of chaeto.

I just reset aquarium with dry rock. Now I have no phosphates. So not currently using it. I set my fugium back up. Well see how it does but don't think I will be able to keep alive.

Well see. I'm also dosing nitrates now. I have lots of fish and feed heavy but it doesn't matter at the moment.
 
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BaliReefBox

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I run 24/7 about 3 tablespoons(60g) of rowa in a mixed carbon gfo reactor. My PO4 constantly sits at about 0.18 with a hanna LR tester. 3 days ago i broke down to 0.09..under 0.10 my target..was so happy had a extra beverage to celebrate. the nest day back to 0.18, day after 0,28 with no change to feeding or anything. Only thing I noticed was a dead hermit crab legs drifting around the tank.(thx camel backs you strike again). missed testing today but will test tomorrow and see how its going.
 
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