Loading... Please wait...


GFO - Grandular Feric Oxide - Do I Need It?

High phosphate levels are a recipe for disaster in saltwater aquariums. It is a nutrient for nuisance algae and also hampers the formation of calcium skeleton in corals. There are several different methods for dealing with phosphate levels but one they I like is using granulated ferric oxide (or GFO) in a media reactor. GFO is best used with a media reactor for several reasons.

First, it is a very fine media and would easily escape from any bag you put it in.

Second, it clumps together if you don't have water moving through it.

When using GFO in a media reactor watch the flow rate of the water through the media. It does not need to be very fast at all. You don't want it looking like boiling water where it is throwing up small particles in the reactor. You just want the very top inch or less turning over ever so slightly like water right before a boil. Otherwise you will get GFO dust all inside your sump and possibly inside your display tank. Depending which reactor you choose, it is a good idea to run the output of the reactor into a filter sock. Worst case scenario some GFO fines get into the filter sock but this way you can avoid the disaster of GFO fines everywhere.
(Mr. Saltwater tank recommends the SpectraPure Dual Media Reactor ( where you can adjust the flow rate through each chamber of the reactor.)
While some people test phosphate levels frequently to know when to change their GFO but I just replace it on my clients' systems at regular intervals. It is just easier that way .
I recommend using GFO from the very beginning of your system so any new corals you put into the system will never get used to elevated levels of phosphate to begin with. Elevated levels of phosphate will usually cause them to brown out because the symbiotic algae inside them overpopulate.
If you already have a phosphate issue and are introducing GFO to a well established reef, start off with a small amount and proceed slowly. Though high phosphate levels aren't good, many corals will not be happy and may even end up dying if you pull the levels down too much, too quickly.
I use and recommend GFO and if your tank already has a high phosphate issue (> 0.10 ppm), start with a little GFO and add more to slowly bring down your phosphates.

Activated Carbon...What is it? Do I Need to Use it?

Activated carbon is a powerful tool for achieving and maintaining good water quality. Carbon removes off-putting smells and yellowing compounds from water. Activated carbon is frangible, which means brittle or fragile. This means that you can crush it into powder easily and create dust. The carbon dust is what you don’t want inside your aquarium as it has been implicated [...]

Read More

Sicce Replacement Skimmer Pump, Which One to Choose?

Below is a list of SICCE Replacement skimmer pumps and the models of skimmers across multiple brands that will fit/run their skimmers.  SICCE engineered their skimmer pumps SK & PSK from the ground up to run with maximum efficiency, low heat and reliability to produce pumps that are beyond compare. Every component of the entire [...]

Read More

Do I Need a Protein Skimmer on My Saltwater Aquarium?

One of the trickiest parts of getting into any new hobby is figuring out what things you actually need and what things are luxuries or things which you can add later. The aquarium industry is like any other hobby where the number of opinions you will run into can become bewildering. Take any facet of [...]

Read More

How Often Should I Change My RO & DI Cartridges?

When you start detecting more chlorine in the waste water it's time to change the carbon. When pressure drops to your RO from normal, change sediment. Change the DI when your TDS rises in the good water. RO membranes should last you many years if you maintain it, flush them, and keep chlorine away from [...]

Read More

RODI Flood Guardian = Game Changer

About once or twice a year a product will be released that is a game changer in the industry.  For 2019, this is it.  This device is what I've been looking for for years.  Basically it's an optical sensor that can go on virtually any bucket/trashcan/etc via magnet that will shut off your RODI when [...]

Read More

Buying a Waterbox or Redsea Reefer, What Else is Needed?

One of the most common questions we get is, I would like to buy a Reefer or Waterbox.  What else do I need to get this thing setup and going?Well, that's a loaded question.  But here are the basics:You Must Have Heater - Warms the water.  Make sure it's rated to or above the total [...]

Read More

Setting Up Amazon Alexa to Work With Apex Fusion

How do I set up Alexa to work with APEX Fusion? A: It takes just a minute to setup the APEX Fusion skill and link your Amazon and APEX Fusion accounts. 1. Sign into your Amazon account using the applicable Alexa web app for your region (,,, or You may also use the [...]

Read More

What's the Deal Apex EL ($499) vs Apex WIFI ($799)

New from Neptune Systems. The Apex EL. EL (Entry Level). A lower cost option to the Apex WFI often referred to as gold. This system will give you access to the Apex world for under $500 bucks. You get everything you need to get started with all the great [...]

Read More

Hurricane Proofing Your Aquarium (Surviving Power Outages)

Power outages suck when you have an aquarium.  We hate hurricane season!  After heater failures, power outages are #2 killer of aquariums and fish.  For fish & corals power outages can be very deadly.The best way to survive a power outage is don't have one.  If your going to invest time, money and effort into [...]

Read More