How do you GFO?

[Spieg]

What is your method for Lanthanum Chloride? If I wanted to add it undiluted, what would you recommend I do? Drops directly into the skimmer? Filter socks?

I used drops into the overflow which feeds into a filter sock (I would install a very fine filter sock of 5-10 microns to catch any particulates created from the process). I'd do this about once every other weekend.

 

[schooncw]

I used drops into the overflow which feeds into a filter sock (I would install a very fine filter sock of 5-10 microns to catch any particulates created from the process). I'd do this about once every other weekend.

Thank you for your reply

 

[schooncw]

I used drops into the overflow which feeds into a filter sock (I would install a very fine filter sock of 5-10 microns to catch any particulates created from the process). I'd do this about once every other weekend.

One more question, if you don't mind: My PO is excessive-about 1.0- in my overstocked and overfed softie tank-most of the rock is 25 or so years old- with no visible problems, except for the lack of coralline algae.
How many drops would you start with? The directions on my bottle are for diluted solutions only.
Thank you for your time!

 

[Randy Holmes-Farley Verified Community Expert]

Do you know if it leaches phosphate back? My method-for my way overstocked and overfed 120-was to put lots in a reactor and just let it run. I'm questioning this now.

Phosphate binding to any media is always an on/off equilibrium.

At any fixed phosphate concentration in the water, some will bind to exposed calcium carbonate, aluminum oxide, GFO, and other surfaces.

If you try to double the amount in the water, you will find that more binds to the surfaces, and the concentration will not quite double.

If you try to halve the amount in the water (say, 50% water change), you will find that some comes off of surfaces, and the concentration will be more than half water it was before.

So if you load up GFO at, say, 1 ppm phosphate, then try to lower the concentration to 0.03 ppm, much will come off the GFO.

 

[Randy Holmes-Farley Verified Community Expert]

I was under the impression that GFO did NOT leach phosphate back as well. Can anyone else comment on this?

Incorrect. I've measured that myself.

 

[schooncw]

Phosphate binding to any media is always an on/off equilibrium.

At any fixed phosphate concentration in the water, some will bind to exposed calcium carbonate, aluminum oxide, GFO, and other surfaces.

If you try to double the amount in the water, you will find that more binds to the surfaces, and the concentration will not quite double.

If you try to halve the amount in the water (say, 50% water change), you will find that some comes off of surfaces, and the concentration will be more than half water it was before.

So if you load up GFO at, say, 1 ppm phosphate, then try to lower the concentration to 0.03 ppm, much will come off the GFO.

Thank you for your reply, I appreciate your time.

 

[Shooter6]

I've never understood why some people take this stance on GFO. It is just a form of nutrient export so why do some have such a negative view of it? Is it because it's not a natural process?
I don't personally see it as being any more of a band aid than running filter socks, protein skimmer, refugium, ATS, etc.

What form(s) of nutrient export do you use and what makes them any less of a band aid than GFO?

Your adding unnecessary chemicals (rusted metal) to your system, to remove phosphate. You really have zero idea what else could be in that rust. Why depend on that when you can instead use a filter pad to trap large particles to remove before they break down, skimmer to remove broken down organics and algae to suck up desolved organics. None of these pose a risk. Also a properly running system has corals, coraline,ect sucking up the phosphate and nitrates too.
Where on gfo dependent systems you have an additional piece added to the system which is keeping the system out of natural balance, and is just another failure point.

 

[brahm]

Phosphate binding to any media is always an on/off equilibrium.

At any fixed phosphate concentration in the water, some will bind to exposed calcium carbonate, aluminum oxide, GFO, and other surfaces.

If you try to double the amount in the water, you will find that more binds to the surfaces, and the concentration will not quite double.

If you try to halve the amount in the water (say, 50% water change), you will find that some comes off of surfaces, and the concentration will be more than half water it was before.

So if you load up GFO at, say, 1 ppm phosphate, then try to lower the concentration to 0.03 ppm, much will come off the GFO.

So what you’re saying is I should sell my used GFO at a premium to folks trying to raise their phosphate

thanks for the clarification! Who said an old dog can’t learn new tricks.

the use case of adding GFO, my phosphates reduce down, and I simply leave said GFO running prior to changing any additional water is there any concern of said GFO leaching back or it will simply find an equilibrium and stay that way?

In addition to that will GFO initially bind a larger amount and then find an equilibrium by shedding some or will it bind what it can and that is that until there is an opportunity for it to re-equalize? (Ie water change).

Essentially is there any value try to time when you swap out the GFO, outside of prior to your next water change?

lastly when you say some comes off, do you mind elaborating from your tests? Say I had a 10 gallons at .1 phosphate added enough GFO to reduce it to .05 phosphate, than replaced 50% of the water with 0 phosphate water. What would that raise my phosphates to .075? Assuming GFO was holding .05, and the remaining .05 was reduced to .025 when I did a 50% water change.

 

[czoolander]

Rarely, but when I use it, it is small amounts in a reactor slightly tumbling changed every day.

GFO will bind quickly and "fill up" fast so you want to use both small amounts and also get it out of there when it is done (change quickly).

GFO can both bind and unbind, so if you change water with old GFO on your tank, it will unbind and fill the water back up again. Remember that your aragonite is likely a reservoir of phosphates, so you have to keep lowering the water column level and allow the rock/sand to unbind. Don't strip the water down to nothing and then have it bounce back up again when the rock unbinds. Use small amounts and change often.

Daily seems excessive for GFO changes ?

I am planning on purchasing a reactor soon for my tank and all the research I have seen has suggest changes every 1-2 months ?

Is the reason you are daily changing so your phosphate doesn't zero out ? or phosphate increases in time if left in the reactor

Thanks ! I have a million GFO /Reactor questions as like I said earlier this is my next purchase I am considering for my reef . I have been reading 0.00 phosphate and have GHA which will be binding up my phosphate . Everything is pointing towards me getting a GFO reactor

 

[jda]

I guess that if it is not in a BRS video, then it is not worth knowing...

Sure, if you use a ton of GFO and you don't change water, then it won't unbind. ...but if you do change water, it will. You will want to change it before any new aragonite from the ocean is added (rock that a coral is on, sand, real rock, etc.) or changing any other media that might lower P like maybe (maybe?) GFO, LC, etc.

Go ahead and use more and don't change it as often and see it somewhat go to waste. It will either all fill up over night (mostly likely) or you won't have enough to fill it up and it will get coated in organics and not be able to bind anything anymore and you wasted a lot of it. Trust me. If you have a phosphate issue that needs lowered, then small amounts changed daily is the most cost efficient and effective way to do this. If you don't have phosphate issues, then you should not be using it at all - there are better ways to keep P in check.

Without knowing surface area of all media and structures, there is no way to calculate numbers, so just go with the fact that it will unbind as much as it would have bound in the reverse... so plenty. A local with a 180g tank and lots of live rock had like .75 ppm of phosphate and it took him more than a 5 gallon bucket of GFO to get to like .05 over nine months. Don't underestimate how much can bind to aragonite and don't underestimate how much you can waste if you leave it in too long or let it unbind from the media.

The binding is exponential - there are plenty of papers and real science out there on this.

 

[jda]

You can find an aragonite binding study that I did in the chemistry forum where 55 ppm of phosphate was added to 10 gallons of water with a phosban reactor about 2/3 full of aragonite. Water was heated. It bound down to a final water concentration of like .16, or something like that. ...so a little binds a lot.

I did this study because people just would not believe that rock and sand bound phosphate... kinda like here, they did not know about it so it was fake news to them. If you can find the thread, Dr. RHF linked some good science to it with some exponential graphs and stuff from some real peer-reviewed stuff. The thread goes off the rails late, but the first few pages are good.

 

[nereefpat]

I haven't had to use GFO in my personal tanks. My phosphate eventually migrates toward unmeasurable.

In service accounts I used to take care of 10-15 years ago, I ran GFO (or Phosguard) in Magnum 250s, which worked surprisingly well. These weren't really reefs, at least not anything beyond cheap easy corals, and I would only run it when there were algae problems and PO4 tested high. I would change it weekly. The tanks also didn't have a hundred pounds of the dry rock that most people start their tanks with now.

The most efficient way would be to run small amounts in a reactor and change it frequently. The same can be said of GAC. If it hasn't already been said, you can test the display water and the output of the reactor. Effluent should be really low, even if the display reads high, unless the media is exhausted. In that case, change it out.

 

[Spieg]

One more question, if you don't mind: My PO is excessive-about 1.0- in my overstocked and overfed softie tank-most of the rock is 25 or so years old- with no visible problems, except for the lack of coralline algae.
How many drops would you start with? The directions on my bottle are for diluted solutions only.
Thank you for your time!

I'd start slow and test to see how much it changes... then adjust the dosage accordingly. Pure LC can be pretty strong, so might be worth diluting with RODI just to be on the safe side.

 

[schooncw]

I'd start slow and test to see how much it changes... then adjust the dosage accordingly. Pure LC can be pretty strong, so might be worth diluting with RODI just to be on the safe side.

I appreciate your response. The PO in my 120 is a consistant1.0-1.50 and think I will start with 4 drops in the overflow.

 

[brahm]

GFO works fine, if it is now known that it leaches back so be it, I’ll leave it in until I do a water change but changing out daily seems like the exact reason why people run into issues with things like GFO because you’d be essentially making moves to quickly and it’s a hassle as long as it’s not something like a curve (@Randy Holmes-Farley )? Where in the first 24 hours it over grabs X amount and then slowly releases back to an equilibrium I’m not going to worry about it.

if you think about it it’s a two way street, and you need to ask is the overall goal to strip phosphates as fast as possible or reduce them. In my case it’s reduce. I’ll still be adding phosphates to the tank via food so as long as I remove the GFO before I reduce the level of phosphates in my tank it will still be a net lose and I don’t need to rip apart a reactor every day. I’ve managed to keep tanks at 0 (per a Hannah) for years so I’m not too worried about not getting the results I want but it is good to know I can get them quicker changing the media every water change vs letting it span 3 water changes or so.

On a side note No reason for condescending tones or comments jda you know many of us have been around a lot longer then brs videos let’s keep the digs on lock and have a discussion.

Not sure what you were getting at in ref to the aragonite are you suggesting swapping sand as a method of p04 reduction? I guess that would help. It’s always been a known you can leach phosphates from rock and sand which is why back in the days it was a Nono to use used live rock or people were doing all that rock baking and dosing things like lc to strip rock before use.