GFO Melting (Granular Ferric Oxide)

[Aqua Splendor]

Hello,
last year I encountered a phenomenon I'd never experienced before: GFO melting like mud.

The tank was starting, and I was scared of phosphate not being taken care of, so I added GFO in a little pouch bag like I usually do (or did).
After a few days, it started to melt, just like mud, it took me a while to notice it and screwed my tank, resulting in an almost instant Clam death once I lift my filter bag and saw the red/orange dripping and RTN/STN following on coral.

The source was from a Local Reef Seller, not the first time I used their stuff.

The only difference I made was mixing carbon, biopellet+another GFO, a Japanese bag I don't remember the name, some leftover, just didn't want to throw it.

I tried to redo this "mistake" but unsuccessfully, I don't have the Japanese bag anymore.

I simply do not understand how this was even possible, I'm curious to know if it happened to you?

 

[Randy Holmes-Farley]

Not sure what happened, but perhaps it wasn't actual GFO.

When you say melted, what actually happened? Did you see material exit the bag?

 

[Aqua Splendor]

Yes, it went from pebble, hard, to liquid form, like ice cream melting in the sun.
The melting occurred for 3-5 days before I noticed it.

 

[Aqua Splendor]

Not sure what happened, but perhaps it wasn't actual GFO.

That's a possibility.
But what I'm intrigued is, if the "Japanese bag" I use wasn't GFO (despite labeled such), not only that one melted but it melted the other brand too, or vice versa. I'm even more intrgued is I reused the same GFO for brand X, nothing happen.

So 2 different sources melted together.

 

[Randy Holmes-Farley]

GFO cannot melt, but it might dissolve or break into smaller particles. The latter is the only one that should happen in a reef tank. Perhaps it was just poorly formed.

 

[Aqua Splendor]

Yeah I was about to add information about that, it didn't disintegrate like if it was in a tube tumbling, making contact with each other, forming ... sand/powder/particle. But it was in a liquid/soft form, no dust at all, no sand or any particle, this is the part that completely blew my mind, it was really like ice cream/mud.

The area it was in, wasn't receiving a lot of flow. If it dissolves in particles I can see it in my sump too but they were just nothing, when I removed the bag, 80% was melted, they were still bit rock left but they were soft, some of them weren't soft(normal). But since I try to redo this 'mistake' I haven't encountered this issue either.

One thing that intrigues me, is the biopellet, but there's a few companies that sell GFO and biopellet together too. So I don't know if one track of this issue could be on the biopellet, but never heard such a reaction and still don't understand how its possible... and yet.

 

[Aqua Splendor]

Hmmm
I think I found the bag, 90% sure it was that:

N/P Reducing BioPellets All-in-One

The positive effects of NP-reducing BioPellets on water quality are based on the principle of immobilization. Waste products from the water, mainly nitrate and phosphate, are converted into bacteria. This keeps the aquarium water clean. The new formula All-In-One Biopellets are composed of...

aquatics.sg

Keeping in mind that it did melt my other *real GFO (?).
I just sent an email to "Reef Secrets" ... not sure about the brand. (Contact us or maybe it's them: Products )

and ... just found a text:

DVH NP All in One Advanced BioPellets

DVH NP All in One Advanced BioPellets

www.fish-street.com

2019 Jan
Our BioPellets is the Latest Version, new dissolve formula
The positive effects of NP-reducing BioPellets on water quality are based on the principle of immobilization. Waste products from the water, mainly nitrate and phosphate, are converted into bacteria
"The pellets will allow aerobic growth of bacteria which consequently will consume nitrate and phosphate simultaneously. The bacteria will use up the carbon from the Reef Interests All-In-One BioPellets whilst nitrogen and phosphorus are taken from the water as nitrate and (ortho)phosphate. This conversion of organic BioPellets (together with inorganic nitrogen and phosphorus) into microbial biomass is called immobilization. In contrast to our “old” Biopellets, we have observed that the All-In-One Biopellets work best with very high water flow.

So this is their new version which I don't think I had. and my reaction was done in 3-5 days. Still not explaining why my other GFO melted or perhaps I say 80% melted, ... which could mean the rest 20% was the actual GFO and didn't melt. hmmm but I do remember mixing a certain portion perhaps not 50% ratio but lower... anyways, will see what they say.

That could explain certain things. Possible it developed bad bacteria too in that mud. (?)

 

[Randy Holmes-Farley]

I do not see any way biopellets caused GFO to dissolve.

 

[Aqua Splendor]

So what about their claim, that product DVH ALL-IN-ONE BIOPELLETS, it's a mix of GFO and Biopellet (I assume polymer form? Carbon source for bacteria?)

the bacteria consumes the pellets for the carbon so they can multiply

The new All-in-One BioPellets has the phosphate remover built in allowing the bacteria to utilize it for growth and reproduction at the same place as their carbon source. This is improves the nitrate removal by about 5x. As the bacteria consume the pellets, a new layer of -fresh- phosphate remover will be exposed for phosphate removal. This makes the All-in-One BioPellets unique in this way.

If that product were to work as they describe, normally I would be left with some pebble after, let say a year correct?

 

[Randy Holmes-Farley]

I don’t know how small their GFO is, but yes, the GFO will remain after the biopellet polymer dissolves away.

 

[Randy Holmes-Farley]

FWIW, this sentence does not seem sensible to me:

The new All-in-One BioPellets has the phosphate remover built in allowing the bacteria to utilize it for growth and reproduction at the same place as their carbon source. This is improves the nitrate removal by about 5x.

 

[jda]

FWIW, this sentence does not seem sensible to me:

The new All-in-One BioPellets has the phosphate remover built in allowing the bacteria to utilize it for growth and reproduction at the same place as their carbon source. This is improves the nitrate removal by about 5x.

...another entry for the false-claim thread.

 

[Aqua Splendor]

FWIW, this sentence does not seem sensible to me:

The new All-in-One BioPellets has the phosphate remover built in allowing the bacteria to utilize it for growth and reproduction at the same place as their carbon source. This is improves the nitrate removal by about 5x.

In the sens that once the phosphate is within the GFO it would be lock and unavailable for bacteria to "extract" it?
Edit: GFO work by Adsorption right? (not Absorption)

 

[Randy Holmes-Farley]

In the sens that once the phosphate is within the GFO it would be lock and unavailable for bacteria to "extract" it?
Edit: GFO work by Adsorption right? (not Absorption)

Yes, and yes.

 

[Aqua Splendor]

Could it be possible with the Anaerobic bacteria to create an environment very acidic and .. release H2S (Hydrogen sulfide) to melt the ferric oxide?

It's a theory that I've been suggested to me.

 

[Randy Holmes-Farley]

Could it be possible with the Anaerobic bacteria to create an environment very acidic and .. release H2S (Hydrogen sulfide) to melt the ferric oxide?

It's a theory that I've been suggested to me.

I do not believe that the pH can get low enough to dissolve the GFO.