Rust in activated carbon?!

ACBlinky · 05/24/2006, 10:36 PM

I opened up the canister filter on my 65g today to change the carbon, and found the white media bag covered in rust stains. I thought maybe it was from something else, even looked to see if there was a screw or razor blade that had somehow found its way into the filter... then I noticed that some of the granules had a reddish colour to them. Is it possible the carbon has tiny particles of metal in it? It's Fluval brand carbon, designed for use in canister filters, and says on the container it's suitable for FW or marine tanks.

Is this rust something anyone else has seen? Anything I should be concerned about?

kevin2000 · 05/25/2006, 11:35 AM

I suspect the "brown stains" your seeing are accumulated debris .. same brown crud you see when changing a std filter. Rust is ferric oxide which is not part of carbon.

ACBlinky · 05/25/2006, 12:09 PM

I really wasn't sure either, but today I tried running a magnet over the carbon and found that about 10% of the particles are magnetic. I'm pretty sure what I'm looking at is rust from some metal in the product, I'm going to write Hagen and ask how the product is made and what their thoughts are about this.
Here's a picture and a closeup, not the best but maybe you can see the particles sticking to the magnet and some of the stains:

itstheantitang · 05/25/2006, 01:50 PM

Wow. I would not expect that from a company like hagen. Good thinking with the magnet test.

When in doubt of the safety and well being of your tank, don't take the risk.

ACBlinky · 05/25/2006, 03:18 PM

I just sent an email to Hagen, letting them know what I found and asking why the product would contain metallic particles. We'll see what they say... I'm wondering if this is a bad batch, it seems very strange that carbon would contain any metal.

reverendmaynard · 05/25/2006, 03:27 PM

It is strange that something packaged as activated carbon would contain iron, but I wouldn't worry about it over much, and it might even have been deliberate. The current, "RC expert" recomended phosphate remover is granulated ferric oxide (GFO), which is really just fancy rust. So, they may have added it to control phosphates. It would be nice if it said so on the package though, huh?

ACBlinky · 05/25/2006, 04:18 PM

Hmm, I never thought about that. Some brands of carbon do raise PO4, your theory makes sense; if GFO reduces PO4 I can see why they'd add it. They really should mention it, and I'm surprised they wouldn't market it as a low phosphate formula or something, when so many of us work hard to reduce phosphates in our tanks, both FW and SW.

Amphiprion · 05/25/2006, 04:43 PM

Ferric oxide IS rust--PO4 removers contain ferric oxide hydroxide. I find it odd that it does have any sort of metallic particles, too. Even if there are some phosphates in the carbon, that little GFOOH would not make a difference.

goda · 05/25/2006, 04:45 PM

nice catch . i wouldent of knoticed that

danny zubot · 05/25/2006, 04:56 PM

Do you have an iron test kit? If the levels are below dangerous I wouldn't worry about it. A certain concentration of iron is acceptable in an aquarium, and can often benifit a reef.

MCary · 05/25/2006, 05:11 PM

Seems like a simple way to dose iron.

ACBlinky · 05/25/2006, 05:49 PM

Danny - I tested for iron, the test showed no free or chelated iron so I guess there's not much to worry about. Still seems odd though, I can't wait to see Hagen's response.

omni2226 · 05/25/2006, 05:57 PM

Well out of curiosity I tested a half jar of carbon I have with a magnet. Its the Regent brand made by Marineland.

Nothing stuck to the magnet. Anyone else reading this have the same brand you have tested theirs? Be interesting to see if its just a small batch or if all that particular brand has bits of iron in it.

05/24/2006, 10:36 PM	#1
ACBlinky Premium Member Join Date: May 2005 Location: Peterborough, ON, Canada Posts: 4,954 Blog Entries: 20	Rust in activated carbon?! I opened up the canister filter on my 65g today to change the carbon, and found the white media bag covered in rust stains. I thought maybe it was from something else, even looked to see if there was a screw or razor blade that had somehow found its way into the filter... then I noticed that some of the granules had a reddish colour to them. Is it possible the carbon has tiny particles of metal in it? It's Fluval brand carbon, designed for use in canister filters, and says on the container it's suitable for FW or marine tanks. Is this rust something anyone else has seen? Anything I should be concerned about?

05/25/2006, 12:09 PM	#3
ACBlinky Premium Member Join Date: May 2005 Location: Peterborough, ON, Canada Posts: 4,954 Blog Entries: 20	I really wasn't sure either, but today I tried running a magnet over the carbon and found that about 10% of the particles are magnetic. I'm pretty sure what I'm looking at is rust from some metal in the product, I'm going to write Hagen and ask how the product is made and what their thoughts are about this. Here's a picture and a closeup, not the best but maybe you can see the particles sticking to the magnet and some of the stains: __________________ "The cure for anything is salt water: sweat, tears, or the sea." - Isak Dinesen Current Tank Info: 150g mixed reef, 30g sump/refugium, LED lighting, 100lbs LR, coral beauty, flame angel, blue & yellow tangs, gobies, damsels, 6-line wrasse, lawnmower blenny, dottyback, clown pair, rabbitfish, shrimp, crabs, CUC.

05/25/2006, 01:50 PM	#4
itstheantitang Registered Member Join Date: Dec 2005 Posts: 477	Wow. I would not expect that from a company like hagen. Good thinking with the magnet test. When in doubt of the safety and well being of your tank, don't take the risk. __________________ Ignore the smoke and smile...

05/25/2006, 03:18 PM	#5
ACBlinky Premium Member Join Date: May 2005 Location: Peterborough, ON, Canada Posts: 4,954 Blog Entries: 20	I just sent an email to Hagen, letting them know what I found and asking why the product would contain metallic particles. We'll see what they say... I'm wondering if this is a bad batch, it seems very strange that carbon would contain any metal. __________________ "The cure for anything is salt water: sweat, tears, or the sea." - Isak Dinesen Current Tank Info: 150g mixed reef, 30g sump/refugium, LED lighting, 100lbs LR, coral beauty, flame angel, blue & yellow tangs, gobies, damsels, 6-line wrasse, lawnmower blenny, dottyback, clown pair, rabbitfish, shrimp, crabs, CUC.

05/25/2006, 03:27 PM	#6
reverendmaynard Registered Member Join Date: Nov 2005 Location: RI Posts: 1,490	It is strange that something packaged as activated carbon would contain iron, but I wouldn't worry about it over much, and it might even have been deliberate. The current, "RC expert" recomended phosphate remover is granulated ferric oxide (GFO), which is really just fancy rust. So, they may have added it to control phosphates. It would be nice if it said so on the package though, huh? __________________ Think for yourself. Question authority. Current Tank Info: 125 gal AGA, setup on 1/1/06; 29 gal seahorse tank, setup 10/21/06

05/25/2006, 11:35 AM	#2
kevin2000 Registered Member Join Date: Jan 2004 Location: Portland, Oregon Posts: 3,805	I suspect the "brown stains" your seeing are accumulated debris .. same brown crud you see when changing a std filter. Rust is ferric oxide which is not part of carbon.

05/25/2006, 04:18 PM	#7
ACBlinky Premium Member Join Date: May 2005 Location: Peterborough, ON, Canada Posts: 4,954 Blog Entries: 20	Hmm, I never thought about that. Some brands of carbon do raise PO4, your theory makes sense; if GFO reduces PO4 I can see why they'd add it. They really should mention it, and I'm surprised they wouldn't market it as a low phosphate formula or something, when so many of us work hard to reduce phosphates in our tanks, both FW and SW. __________________ "The cure for anything is salt water: sweat, tears, or the sea." - Isak Dinesen Current Tank Info: 150g mixed reef, 30g sump/refugium, LED lighting, 100lbs LR, coral beauty, flame angel, blue & yellow tangs, gobies, damsels, 6-line wrasse, lawnmower blenny, dottyback, clown pair, rabbitfish, shrimp, crabs, CUC.

05/25/2006, 04:43 PM	#8
Amphiprion Premium Member Join Date: Jul 2005 Location: Mobile, AL Posts: 6,611	Ferric oxide IS rust--PO4 removers contain ferric oxide hydroxide. I find it odd that it does have any sort of metallic particles, too. Even if there are some phosphates in the carbon, that little GFOOH would not make a difference. __________________ You've done it now, haven't you? Current Tank Info: 40g breeder patch reef w/ seagrass; 2-250w XM 10K; Vortech MP40wES & MP10wES; BM Curve 7 skimmer; carbon & occasional GFO

05/25/2006, 04:45 PM	#9
goda Moved On Join Date: Mar 2006 Location: fortlauderdale florida area Posts: 1,874	nice catch . i wouldent of knoticed that

05/25/2006, 04:56 PM	#10
danny zubot Registered Member Join Date: Apr 2004 Location: Castlegar, BC, Canada Posts: 84	REPLY Do you have an iron test kit? If the levels are below dangerous I wouldn't worry about it. A certain concentration of iron is acceptable in an aquarium, and can often benifit a reef. __________________ Frags for sale in the Kootenay's Current Tank Info: 55 gallon cube mixed reef, 30 gallon sump, 10 gallon fuge, 400 watt XM 20K with dual 24" HO T5 German Actinics, ASM G3 skimmer, Pinpoint PH monitor, Dual chamber PO4 & Nitrate reactor, CPR Overflow, Mag 9.5 return through SQWD, 3 Koralia 2's

05/25/2006, 05:11 PM	#11
MCary Premium Member Join Date: Dec 2002 Location: Hardin, Montana Posts: 3,142	Seems like a simple way to dose iron.

05/25/2006, 05:49 PM	#12
ACBlinky Premium Member Join Date: May 2005 Location: Peterborough, ON, Canada Posts: 4,954 Blog Entries: 20	Danny - I tested for iron, the test showed no free or chelated iron so I guess there's not much to worry about. Still seems odd though, I can't wait to see Hagen's response. __________________ "The cure for anything is salt water: sweat, tears, or the sea." - Isak Dinesen Current Tank Info: 150g mixed reef, 30g sump/refugium, LED lighting, 100lbs LR, coral beauty, flame angel, blue & yellow tangs, gobies, damsels, 6-line wrasse, lawnmower blenny, dottyback, clown pair, rabbitfish, shrimp, crabs, CUC.

05/25/2006, 05:57 PM	#13
omni2226 Premium Member Join Date: Feb 2006 Location: Middle Florida Posts: 774	Well out of curiosity I tested a half jar of carbon I have with a magnet. Its the Regent brand made by Marineland. Nothing stuck to the magnet. Anyone else reading this have the same brand you have tested theirs? Be interesting to see if its just a small batch or if all that particular brand has bits of iron in it. __________________ I know enough to know I know nothing. Current Tank Info: 55 Marine. 29 Freshwater planted.