Regenerating GFO - Page 3

schnitm · 11/15/2009, 12:54 PM

Tested the solution last night after the GFO had been in the second batch for about 24 hours. Did exactly as before...stirred the GFO, took out some of the lye solution and diluted with RODI 100:1. Tested phosphate and got a reading of about 0.5. This had read about 1.0 after 4 hours with the first batch of lye.

The I used some distilled white vinager to get the PH to about 8.0. Took a few tries. This time it read about 1.0ppm phosphate. About double the reading I got with the high, unadjusted PH. I managed to overshoot once and got a PH below the range of my test kit (less than 7.4). From the PH test color I'd say I overshot a lot. That read 3.0 phosphate. I'm assuming the 1.0 is about right.

If the doubling is right, my first batch of lye was at 200ppm phosphate and the second 100. 4 liters each time so 1200mg total removed from the GFO so far. There's about 700 liters in my system. The GFO droped the phosphate from about 1 to close to zero in 4 days. So it took about 700mg that was originally in the water plus at least 500mg more that must have leached out of the rock or come from food. I fed the tank about 20g of Rod's H total over the 4 days (5 grams each day).

The tank reads about 0.5ppm phosphate this morning. Up from 0.05 to 0.5 in less than 48 hours, about 350mg.

Randy Holmes-Farley · 11/15/2009, 06:07 PM

Very interesting data, including how fast your tank leaps back up in phosphate. You may have a long way to go to strip all that out.

Randy Holmes-Farley · 12/19/2009, 02:42 PM

So Tatu, what are you thinking about the regeneration process these days?

tatuvaaj · 12/20/2009, 01:17 AM

Still using the same batch of GFO, now regenerated four or five times

I haven't tested how well the material still binds PO4 but at least the tank water is constantly around 0.03 ppm. I'll get some fresh GFO in a few weeks and do comparison between them.

Some notes:
- The GFO seems to draw a lot of CaCO3 from water. Takes a good amount of 10% vinegar to get all out

- The color of GFO seems to get darker each time it is regenerated (?) I've been using more concentrated solution (up to 3M) and less than the recommended 3-4:1 water:GFO.
- Some heat is generated during the first hours of regeneration
- It takes a lot of rinsing to get "all" of the NaOH out

Randy Holmes-Farley · 12/20/2009, 08:26 AM

Thanks for the update.

Psionicdragon · 12/26/2009, 04:07 AM

anymore updates

?

ScooterTDI · 12/30/2009, 09:29 PM

I had a hard time finding pure NaOH drain cleaner, so I tried regenerating some GFO last night with 50% vinegar solution. It seemed to work well. The phosphate concentration of the soak solution was off the charts. I'm not sure if vinegar will foul the GFO surface though. I may try hydrochloric acid next time.

Scott

tatuvaaj · 01/01/2010, 02:19 AM

Scott,

Thanks!

I use vinegar as a first step in regeneration. I was surprised at the amount of carbonates deposited on GFO but never tested PO4 in the used vinegar

ScooterTDI · 01/01/2010, 07:07 PM

No problem,

Next time I'll test some dilutions to quantify the amount of phosphate stripped from the GFO with an acid treatment alone. The vinegar bath treatment seems to be working well enough. The regenerated GFO is keeping phosphates low, 0.01 mg/L according to the Elos kit.

Scott

plankton · 01/02/2010, 01:40 AM

You should be able to buy 'caustic lye', 'lye', 'caustic soda' from any local soapmaker supply shop (if you have one).

- Tagging along...great discussion and glad I saved all my old GFO!

Scott

redfishsc · 01/02/2010, 08:04 AM

I've often wondered if old GFO would work as a plant substrate in freshwater systems. Folks who dose CO2 in their planted tanks generally need a phosphate source and iron source, both of which GFO would provide.

schnitm · 01/02/2010, 11:23 PM

My regenrated GFO has been in the reactor for about 6 weeks now. I agree that it is darker than the fresh stuff. Also, agree that it is hard to rinse all of the NAOH off. Didn't get all of that "soapy" feeling to go away but put it in anyway. My system has been running undetectable (by Sailfert) phosphate since about two days after the regenerated GFO whet in.

Conditions in the display are excellent! No algae or cyano. I do clean the glass every two or three days. I see no negative impact on my ATS, solid growth and undetectable nitrates by the sensitive Sailfert test.

Plan to take it out on Wednesday and replace with fresh while I regenerate this batch. I think I'll hold on the GFO until Friday to see what happens. I am interested to see the effect of an equal amount of fresh GFO. However, there's nothing in the tank that hasn't seen phosphates over 0.5 so, in the interests of science, why not wait and see if my rock is still leeching beyond the ability of the ATS to absorb it.

schnitm · 01/09/2010, 03:52 PM

GFO has been out of my system and in NAOH since Wednesday. I did not detected phosphates in my system using my Sailfert kit until this afternoon. Even now it's just a hint of blue. Everything in the "nitrogen family" remains undetectable.

However, my glass has needed cleaning daily since removing the GFO and I'm getting some thin green growth on some of the rock in the display. Also, I've had a small colony of red/brown flatworms all along. The flatworm population has jumped up and they are darker. They were light brown before and are now rust colored.

Last bit. My ATS has grown thicker than ever since I removed the GFO. The screens are very heavy and I need to clean them early.

Am going to put some fresh HC GFO back in in a bit. I think I'll start with about a third of what I had and see what happens.

plankton · 01/12/2010, 09:15 PM

Randy - So, what's the best recipe thus far to regenerate GFO? Just acid wash or acid, then base... or what? Thanks in advance...

Scott

solos2 · 01/12/2010, 09:54 PM

Quote:

Originally Posted by Bob 1000

Thanks for the update.. I'll be following this thread even though I use strontium nitrate for my phosphate reduction..

p.s. a little off-topic, but how do you use strontium nitrate for that purpose, and wouldn't that nitrate dissolve into the water, ie. BAD?

richierich2000 · 01/12/2010, 09:54 PM

So, what's the best recipe thus far to regenerate GFO? Just acid wash or acid, then base... or what? Thanks in advance...

+1

PaxRoma · 01/12/2010, 11:09 PM

very interesting development. I'll be sure to subscribe. I hope Randy or someone will come out with an article on this.

badonkadonk · 01/13/2010, 01:53 PM

I've been regenerating my GFO using NaOH pellets (dissolved in water, of course, to 1 M) several times by now. I first mix the spent GFO with about 3x the volume of GFO in a bucket and decant the liquid, then repeat 2 more times. I let the GFO sit in the second and third washes of hydroxide solution for a few hours each, and give it an occassional stir if I happen to be around. I don't know whether the GFO is porous that it takes a while to leach, but figure it can't hurt. Then I repeat the rinses with RO/DI water 3 or 4 times, and then pour the GFO into mesh nylon filter socks and hang them up to drip dry. Then I dip the filter socks into pitchers of RO/DI water a few more times (changing the RO/DI between soaks), allowing the water to drip out between each batch. I finish up by dipping the filter socks into tank water (saved from a water change) to buffer out any remaining hydroxide, and finally hit it with more RO/DI before I let it completely dry and pour it back into a container for storage. It may sound like a lot of work, but mostly it is just time spent soaking/draining and only takes a minute for each step. And the GFO doesn't have to be pre-rinsed next time you use it. Also I have a fair amount of GFO from various sources all mixed together - Phosban, the Dr. FosterSmith brand, BRS, etc., and do the batch of 5 or more pounds all at once. I bought the NaOH online, just do a Google search for it, I got mine from AAA-Chemicals.

SWINGRRRR · 01/16/2010, 03:13 PM

Quote:

Originally Posted by badonkadonk

I first mix the spent GFO with about 3x the volume of GFO in a bucket and decant the liquid, then repeat 2 more times.

I dont understand this statement.

joao junior · 01/16/2010, 06:06 PM

if rowaphos can be regerate too??

elijaher · 01/16/2010, 07:35 PM

Be nice if picture on this process.

AcroporAddict · 01/17/2010, 07:41 AM

It seems like you really shouldn't have to rinse the GFO as much as people seem to be doing here. GFO is non-porous from my understanding, so you are only rinsing the NaOH from the surface. Seems all you need to do is put the regenerated GFO in a filter bag and rinse a few times by dipping in tapwaster or RODI or run tapwater in thru the top of the bag and thru the GFO a couple times.

or am I wrong here?

ScooterTDI · 01/17/2010, 09:05 AM

Quote:

Originally Posted by SWINGRRRR

I dont understand this statement.

I believe he is saying that he is using a volume of regeneration solution equal to 3 times the volume of the GFO he is regenerating, i.e 300 mL of solution for 100 mL of GFO.

Scott

ScooterTDI · 01/17/2010, 09:06 AM

Quote:

Originally Posted by joao junior

if rowaphos can be regerate too??

yes.

ScooterTDI · 01/17/2010, 09:08 AM

Quote:

Originally Posted by AcroporAddict

It seems like you really shouldn't have to rinse the GFO as much as people seem to be doing here. GFO is non-porous from my understanding, so you are only rinsing the NaOH from the surface. Seems all you need to do is put the regenerated GFO in a filter bag and rinse a few times by dipping in tapwaster or RODI or run tapwater in thru the top of the bag and thru the GFO a couple times.

or am I wrong here?

Well, GFO is fairly porous, but I don't think the concern is necessarily NaOH, but rather getting all of the PO4 enriched solution out of the GFO.

Scott

11/15/2009, 06:07 PM	#52
Randy Holmes-Farley Reef Chemist Join Date: Apr 2001 Location: Arlington, Massachusetts Posts: 86,233	Very interesting data, including how fast your tank leaps back up in phosphate. You may have a long way to go to strip all that out. __________________ Randy Holmes-Farley Current Tank Info: 120 mixed reef

12/19/2009, 02:42 PM	#53
Randy Holmes-Farley Reef Chemist Join Date: Apr 2001 Location: Arlington, Massachusetts Posts: 86,233	So Tatu, what are you thinking about the regeneration process these days? __________________ Randy Holmes-Farley Current Tank Info: 120 mixed reef

12/20/2009, 01:17 AM	#54
tatuvaaj Pro-Protozoa Join Date: Nov 2000 Location: Tampere, Finland Posts: 1,228	Still using the same batch of GFO, now regenerated four or five times I haven't tested how well the material still binds PO4 but at least the tank water is constantly around 0.03 ppm. I'll get some fresh GFO in a few weeks and do comparison between them. Some notes: - The GFO seems to draw a lot of CaCO3 from water. Takes a good amount of 10% vinegar to get all out - The color of GFO seems to get darker each time it is regenerated (?) I've been using more concentrated solution (up to 3M) and less than the recommended 3-4:1 water:GFO. - Some heat is generated during the first hours of regeneration - It takes a lot of rinsing to get "all" of the NaOH out __________________ Tatu Vaajalahti Tampere, Finland Current Tank Info: 240 gal + 50 gal sump,SDSB,LR,ATB Medium, 2x250W HQI + actinic,Balling

12/20/2009, 08:26 AM	#55
Randy Holmes-Farley Reef Chemist Join Date: Apr 2001 Location: Arlington, Massachusetts Posts: 86,233	Thanks for the update. __________________ Randy Holmes-Farley Current Tank Info: 120 mixed reef

12/26/2009, 04:07 AM	#56
Psionicdragon Registered Member Join Date: Dec 2002 Location: San Francisco Posts: 3,727	anymore updates ? __________________ Economy sucks bad! Lets pray for the best! in the meantime, liquidation!

11/15/2009, 12:54 PM	#51
schnitm Registered Member Join Date: Oct 2009 Location: St. Louis Posts: 104	Tested the solution last night after the GFO had been in the second batch for about 24 hours. Did exactly as before...stirred the GFO, took out some of the lye solution and diluted with RODI 100:1. Tested phosphate and got a reading of about 0.5. This had read about 1.0 after 4 hours with the first batch of lye. The I used some distilled white vinager to get the PH to about 8.0. Took a few tries. This time it read about 1.0ppm phosphate. About double the reading I got with the high, unadjusted PH. I managed to overshoot once and got a PH below the range of my test kit (less than 7.4). From the PH test color I'd say I overshot a lot. That read 3.0 phosphate. I'm assuming the 1.0 is about right. If the doubling is right, my first batch of lye was at 200ppm phosphate and the second 100. 4 liters each time so 1200mg total removed from the GFO so far. There's about 700 liters in my system. The GFO droped the phosphate from about 1 to close to zero in 4 days. So it took about 700mg that was originally in the water plus at least 500mg more that must have leached out of the rock or come from food. I fed the tank about 20g of Rod's H total over the 4 days (5 grams each day). The tank reads about 0.5ppm phosphate this morning. Up from 0.05 to 0.5 in less than 48 hours, about 350mg.

12/30/2009, 09:29 PM	#57
ScooterTDI Registered Member Join Date: Apr 2007 Posts: 290	I had a hard time finding pure NaOH drain cleaner, so I tried regenerating some GFO last night with 50% vinegar solution. It seemed to work well. The phosphate concentration of the soak solution was off the charts. I'm not sure if vinegar will foul the GFO surface though. I may try hydrochloric acid next time. Scott __________________ "the profusion of tildes" - Leonard A. Smith

01/01/2010, 02:19 AM	#58
tatuvaaj Pro-Protozoa Join Date: Nov 2000 Location: Tampere, Finland Posts: 1,228	Scott, Thanks! I use vinegar as a first step in regeneration. I was surprised at the amount of carbonates deposited on GFO but never tested PO4 in the used vinegar __________________ Tatu Vaajalahti Tampere, Finland Current Tank Info: 240 gal + 50 gal sump,SDSB,LR,ATB Medium, 2x250W HQI + actinic,Balling

01/01/2010, 07:07 PM	#59
ScooterTDI Registered Member Join Date: Apr 2007 Posts: 290	No problem, Next time I'll test some dilutions to quantify the amount of phosphate stripped from the GFO with an acid treatment alone. The vinegar bath treatment seems to be working well enough. The regenerated GFO is keeping phosphates low, 0.01 mg/L according to the Elos kit. Scott __________________ "the profusion of tildes" - Leonard A. Smith

01/02/2010, 01:40 AM	#60
plankton Registered Member Join Date: Jan 2000 Location: Pleasanton, CA Posts: 2,676	You should be able to buy 'caustic lye', 'lye', 'caustic soda' from any local soapmaker supply shop (if you have one). - Tagging along...great discussion and glad I saved all my old GFO! Scott

01/02/2010, 08:04 AM	#61
redfishsc Registered Member Join Date: Sep 2008 Location: Wake Forest, NC Posts: 3,696	I've often wondered if old GFO would work as a plant substrate in freshwater systems. Folks who dose CO2 in their planted tanks generally need a phosphate source and iron source, both of which GFO would provide. __________________ "The measure of a life is not its duration but its donation." Corrie Ten Boom “The tyrant dies and his rule is over, the martyr dies and his rule begins” -- Søren Kierkegaard Current Tank Info: ghetto grad school reef.....11g rimless tank, 36X9X9, lit by Cree and Rebels scobbled together. Stocked mostly with free stuff I got from panhandling my fellow reefers.

01/02/2010, 11:23 PM	#62
schnitm Registered Member Join Date: Oct 2009 Location: St. Louis Posts: 104	My regenrated GFO has been in the reactor for about 6 weeks now. I agree that it is darker than the fresh stuff. Also, agree that it is hard to rinse all of the NAOH off. Didn't get all of that "soapy" feeling to go away but put it in anyway. My system has been running undetectable (by Sailfert) phosphate since about two days after the regenerated GFO whet in. Conditions in the display are excellent! No algae or cyano. I do clean the glass every two or three days. I see no negative impact on my ATS, solid growth and undetectable nitrates by the sensitive Sailfert test. Plan to take it out on Wednesday and replace with fresh while I regenerate this batch. I think I'll hold on the GFO until Friday to see what happens. I am interested to see the effect of an equal amount of fresh GFO. However, there's nothing in the tank that hasn't seen phosphates over 0.5 so, in the interests of science, why not wait and see if my rock is still leeching beyond the ability of the ATS to absorb it.

01/09/2010, 03:52 PM	#63
schnitm Registered Member Join Date: Oct 2009 Location: St. Louis Posts: 104	GFO has been out of my system and in NAOH since Wednesday. I did not detected phosphates in my system using my Sailfert kit until this afternoon. Even now it's just a hint of blue. Everything in the "nitrogen family" remains undetectable. However, my glass has needed cleaning daily since removing the GFO and I'm getting some thin green growth on some of the rock in the display. Also, I've had a small colony of red/brown flatworms all along. The flatworm population has jumped up and they are darker. They were light brown before and are now rust colored. Last bit. My ATS has grown thicker than ever since I removed the GFO. The screens are very heavy and I need to clean them early. Am going to put some fresh HC GFO back in in a bit. I think I'll start with about a third of what I had and see what happens.

01/12/2010, 09:15 PM	#64
plankton Registered Member Join Date: Jan 2000 Location: Pleasanton, CA Posts: 2,676	Randy - So, what's the best recipe thus far to regenerate GFO? Just acid wash or acid, then base... or what? Thanks in advance... Scott

01/12/2010, 09:54 PM	#66
richierich2000 SPS Crazy Join Date: Oct 2003 Location: Jeffersonville,Ohio Posts: 1,083	So, what's the best recipe thus far to regenerate GFO? Just acid wash or acid, then base... or what? Thanks in advance... +1 __________________ -Rich- Current Tank Info: 180 gallon mixed reef and 125 gallon anemone/frag tank

01/12/2010, 11:09 PM	#67
PaxRoma Registered Member Join Date: Jan 2009 Location: H town, TX Posts: 421	very interesting development. I'll be sure to subscribe. I hope Randy or someone will come out with an article on this.

01/13/2010, 01:53 PM	#68
badonkadonk Registered Member Join Date: May 2005 Location: Malibu, CA Posts: 227	I've been regenerating my GFO using NaOH pellets (dissolved in water, of course, to 1 M) several times by now. I first mix the spent GFO with about 3x the volume of GFO in a bucket and decant the liquid, then repeat 2 more times. I let the GFO sit in the second and third washes of hydroxide solution for a few hours each, and give it an occassional stir if I happen to be around. I don't know whether the GFO is porous that it takes a while to leach, but figure it can't hurt. Then I repeat the rinses with RO/DI water 3 or 4 times, and then pour the GFO into mesh nylon filter socks and hang them up to drip dry. Then I dip the filter socks into pitchers of RO/DI water a few more times (changing the RO/DI between soaks), allowing the water to drip out between each batch. I finish up by dipping the filter socks into tank water (saved from a water change) to buffer out any remaining hydroxide, and finally hit it with more RO/DI before I let it completely dry and pour it back into a container for storage. It may sound like a lot of work, but mostly it is just time spent soaking/draining and only takes a minute for each step. And the GFO doesn't have to be pre-rinsed next time you use it. Also I have a fair amount of GFO from various sources all mixed together - Phosban, the Dr. FosterSmith brand, BRS, etc., and do the batch of 5 or more pounds all at once. I bought the NaOH online, just do a Google search for it, I got mine from AAA-Chemicals. Last edited by badonkadonk; 01/13/2010 at 01:57 PM. Reason: added info

01/16/2010, 06:06 PM	#70
joao junior Registered Member Join Date: Oct 2006 Posts: 251	if rowaphos can be regerate too??

01/16/2010, 07:35 PM	#71
elijaher Registered Member Join Date: Sep 2007 Location: Kansas City,Missouri Posts: 1,188	Be nice if picture on this process.

01/17/2010, 07:41 AM	#72
AcroporAddict There is no substitute. Join Date: Apr 2008 Location: Southeast Posts: 2,269	It seems like you really shouldn't have to rinse the GFO as much as people seem to be doing here. GFO is non-porous from my understanding, so you are only rinsing the NaOH from the surface. Seems all you need to do is put the regenerated GFO in a filter bag and rinse a few times by dipping in tapwaster or RODI or run tapwater in thru the top of the bag and thru the GFO a couple times. or am I wrong here?