View Full Version : GFO questions

12/20/2010, 11:30 AM
I'm not new to the hobby but I had taken a couple year break from the hobby and Now I've got a 90g in wall tank up and running for about 60 days now. In the past I didnt have much equipment besides a skimmer and lights. So all of this GFO, bio balls, reactor stuff is new and a bit confusing to me.

How necessary and effective is GFO?

my phosphates are low as of now but I can bet as time goes on this stuff may accumulate in the system so i'm thinking I should get something online to combat it.

Also does haveing a GFO reactor negate the use of a refugium?

-Lead me in the right direction.

I dont want to have this thing stcked full and have to completly redesign the system.


12/20/2010, 11:55 AM
I am certain you will receive more detailed answers, but just a few basics.

Does your DT have a sump attached below? If you have a sump that has compartments, you would / could have one compartment dedicated to your skimmer, and another act as a refugium. The GFO I don't believe really negates the total benefits of a refugium. Although a refugium can act to export nutrients (Nitrates & PO4), they also cultivate pods, and other beneficial critters for your fish / corals. Most people grow a macroalgae in their refugium, something like chaeto.

GFO can be placed in a reactor (in-line) or if you have a filter compartment, it can be added to a filter bag and utilized that way. The reactor will ensure more effective surface area flowing around the media, but filter bags will work as well.

A lot of this depends on what type of tank you are setting up, whether fish only with live rock (FOWLR), or a reef tank. If corals, then you could further define with what type of corals you will be keeping. Some require very pristine water conditions while others may even enjoy a little extra nutrients in the water. Some receive most of their food source from light, while others require more purposeful feedings which can be supplemented with an active refugium.

Anyway...hope some of this helps.


12/20/2010, 12:02 PM
I'm learning too so, hopefully this helps you. The idea behind reactors is to export organics, nutrients, and phosphates.

GFO - Primarily is a phosphate export system.
Carbon - Primarily organics and/ or nutrient export system.

Regugium: Nutrient / phosphate export system.
Algae Turf Scrubber (ATS): Nutrient / Phosphate export system.
Water changes: Nitrate/ Nutrient, and phosphate export system.

Cyano and nuisance hair algae: Nutrient and phosphate export system.

Do you see a trend? heh. The last one is the system you really really really don't want to allow to get established. If you use GFO you probably won't need a refugium, and may have competing resource issues between the refugium and the GFO. An ATS and refugium would compete with each other for resources.

For me, I have a huge phosphate issue, so have multiple export mechanisms in place: GFO, ball of Chaeto, and ATS. Obviously, long term, all 3 will not function together. At some point something will have to be shut down. I may change out the GFO to carbon in the BRS reactor and keep the ATS and Chaeoto. That's a general overview of the purpose.

12/20/2010, 02:04 PM
You will likely need some sort of PO4 control. GFO is probably the most effective/easiest to use; hence its popularity/ prevealnce in the hobby.

It does not negate a refugium, but algae harvesting from the 'fuge may be reduced.

12/20/2010, 06:39 PM
What is the measured phosphate level in your tank? What would your goals be for reducing the phosphate level? Some people try to change coral coloration using low-nutrient approaches, for example. Others are just worrying about basic health.