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GFO and Algae

Posted 10/04/2014 at 12:04 PM by Sk8r

Do you need GFO: how to use it...RE PHOSPHATE AND ALGAE PLAGUE
Granulated Ferrous Oxide is, in effect, rusty iron pellets made porous, specifically to sop up and hold phosphate out of your water.

Rock, sand, and tapwater all contribute phosphate to your tank, and algae loves it...especially hair and film algae. Some rock is worse than others in this regard---but it can be some of the prettier rock. And 'new' rock goes through a period when it starts slowly 'leaking' phospate into your water. Can this be helped? Yes. With a GFO reactor.

A refugium with cheatomorpha algae is capable of sopping up a little phosphate. But not nearly enough to solve a hefty algae outbreak in your DT, and by that I mean anything from film on your glass to waving sheets of green hair 6" long over every surface in the tank.

A phosphate test? Not so helpful. You can apply a phosphate test to the green hairy tank and get 'zero'. Why? Because the very high phosphate level is bound up inside the algae where the test can't read it.

Exporting via wind-and-yank and toss? Oh, yes. I did this on one really bad tank, getting a couple of pounds of algae out per go. No improvement. It would regrow. And regrow. And regrow.

GFO in a reactor solved it in about 4 months. 'Rocks as bald as an egg'-type solved. If you're dealing with new rock, you may have to go a bit longer, til the rock has given up the last of its supply, but 3-4 months will usually solve even the worst cases, problem rock and all.

Brand I used: Phosban. Need it be in a reactor? Pretty well yes. Putting it in a bag in your waterflow does NOT get it to work as efficiently as it will in a reactor chamber, where every particle is floating---what you call a 'fluidized bed.' The reactors, fortunately, are fairly cheap, and are good to have should, for instance, you ever forget to change your ro/di media and you get another outbreak. You can also run carbon or NPX beads in the reactor.

Now, GFO has one outstanding virtue: what it absorbs, it hangs onto. [Carbon, for instance, saturates and then starts breaking down and distributing what it collected back into your water...] So if you never changed it, it would not let go of the phosphate. BUT!@!!! it's also full-up, and can't take any more phosphate if you left it in there a century...and...bad point! doesn't change color or let you know it's full-up. You could run that load forever and get no more phosphate out of your tank.

Now, this is NOT what the instructions say, but this is what I advise, if you have a lot of algae: run your first load (of Phosban, the dose being 1 jar per 50 gallons of tank: and yes, there are reactors that hold 2 jars at once: the smaller reactors only hold one, and you should NOT overload the reactor.) ---Run your reactor one month, then if there's been no cure yet, change the medium for new. Run it another month. Change the medium. Keep this up until you see bare rocks. Yes, it's a little spendy, but it works. I would suppose that in a 200 gallon tank you could make a single-dose reactor work---it might just take longer.

Beyond that, you should not have that much film or hair algae. Remove the reactor and clean it out and store it, or set it to running NPX or the like. If algae starts showing up again, first thing to check is your ro/di filter. And run the reactor until you solve your problem.

Is phosphate necessary? Fish and corals aren't fond of it. Algae loves it.

Will its absence do in your refugium algae? No. Possibly running it forever could harm it, but it certainly did no damage to that algae in my fuge.

One other note: when you feed green, algae-based fish food, or phytoplankton in green liquid, you are adding in a little phosphate. Should you have an excess of this sort of feeding, you might be adding a bit, but if you have that reactor in reserve, to be used any time you start seeing an excess of film shouldn't have a problem with that source.

Hope that helps clear up some of the confusion
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  1. New Comment
    hanksweb's Avatar
    Thank you very much for sharing your knowledge! I have a 3 month tank that has been showing hair algae for about 2 weeks. I started phosban in a reactor last week and was wondering why I didn't see an improvement. Thanks to you, I have a new time expectation. I feel much better.
    Posted 10/31/2014 at 09:24 AM by hanksweb hanksweb is offline
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    Posted 08/26/2015 at 02:29 AM by Harrhugh Harrhugh is offline
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    Posted 03/05/2016 at 01:38 AM by zohoki zohoki is offline

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