GFO basically useless in very high phosphate environment?

[BigJohnny]

https://www.researchgate.net/public...val_Demonstration_preparation_and_field_study

I only had access to the abstract and figures for the article above, but from what little I could readof it, I would use 50 mg PO4 per gram of GFO as a high estimate of its capacity. How it is made and stored and how old it is effects the capacity. Using this generous capacity will prevent removing PO4 too quickly from your system.

Thanks bud, exactly the sort of thing I was looking for. I know there are many variables but all I was hoping for was an estimate.

 

[BigJohnny]

Can I ask why no large water change? Seems the least detrimental and most controlable

You changed your question, originally this said can I ask why no LC, so that's what I responded to. It appears that has updated to "why no large water change" on your original post as well as the quoted post where I responded.

I dont want to do a large water change for several reasons, but mainly because I want to reduce the phosphate level very slowly from .5 to let's just say .15 ppm at a rate no faster than .03 per day, .1 per week, or if using LC or a water change, .03ppm per instant/use. In that case I would need to do about 11 water changes which is a lot obviously.

 

[Big E]

I've had similar spikes and used GFO in a reactor. I use half the recommended amount and just run it for 6 hours. Take a day or two off line and then work it down a bit more.
I knocked it down approx .15 per use. In about 8-10 days I had it down to my target range.

Trying to do it in a bag passively is going to be a fruitless endeavor.

 

[BigJohnny]

I've had similar spikes and used GFO in a reactor. I use half the recommended amount and just run it for 6 hours. Take a day or two off line and then work it down a bit more.
I knocked it down approx .15 per use. In about 8-10 days I had it down to my target range.

Trying to do it in a bag passively is going to be a fruitless endeavor.

Thanks for posting.

Did you knock it down .15 ppm per use without any issues or stress to corals? How long was your phosphate spiked before you started reducing it?

Why do you say using gfo in a bag passively is a fruitless endeavor? It just takes longer in a bag than in a reactor, which is what I want. As long as the media doesnt clump it will still work properly.

I have had corals pale when I've dropped phosphate faster that .1 ppm per day, so .15 ppm in 6 hours concerns me. Maybe since the levels are so high now it wouldnt stress them out as much, I dont know.

My issue has more been guessing when the media is exhausted since my test kit jumps from .5 ppm to .3 ppm. You can see shades in between but it's a guessing game until I get to < .3 ppm.

 

[Big E]

Did you knock it down .15 ppm per use without any issues or stress to corals? How long was your phosphate spiked before you started reducing it?

I didn't target .15 drop I just decided to run GFO for 6-8 hours so not to stress anything. The high levels were .45-.50, so dropping .15 short term isn't going to hurt much. I've had rises that happened in a week or so and other times when it took a few months. These happened due to changes in the system, so once I worked it back down the system fell back into a baseline. For example I had about 6 anthias and I fed the crap out of them and didn't realize till a few months later when growth slowed and more algae was showing up. Some short term spike examples were stopping carbon dosing and livestock losses.

Why do you say using gfo in a bag passively is a fruitless endeavor? It just takes longer in a bag than in a reactor, which is what I want. As long as the media doesnt clump it will still work properly.

No it won't...............at least for me it never did and I've tried it more than once.

You may get a small drop at first but unless you have water flowing through the bag you aren't going to get much of a consistent change that will hold. I have had a bag sit below high flow skimmer outputs and that works. Just putting a bag in the sump is very inefficient. The other problem is that without the flow/movement the bag will get covered in bacteria fast and just clog it up from doing anything.

I have had corals pale when I've dropped phosphate faster that .1 ppm per day, so .15 ppm in 6 hours concerns me. Maybe since the levels are so high now it wouldnt stress them out as much, I dont know.

If you're going from .15 to .05 that can be problematic, but from the higher levels it's not a problem. I've gone from .25 to .13-.15 and everything was fine.

My issue has more been guessing when the media is exhausted since my test kit jumps from .5 ppm to .3 ppm. You can see shades in between but it's a guessing game until I get to < .3 ppm.

You need to use a Hannah 736 to really know where you're at. It isn't that important to get perfect accuracy but consistency in readings. There isn't a reason to split hairs and excessively test when doing something like this.
Keep in mind the .15 is just a working target........if you went down a bit more it's not a cause for alarm.

I don't mess with trying to drop low ranges. If my tank readout was .15 I wouldm't mess with it but just monitor. If over weeks or months it's worked up higher then I would do something. People get in trouble trying to micro manage every 100th of a ppm at lower levels.

 

[BigJohnny]

Did you knock it down .15 ppm per use without any issues or stress to corals? How long was your phosphate spiked before you started reducing it?

I didn't target .15 drop I just decided to run GFO for 6-8 hours so not to stress anything. The high levels were .45-.50, so dropping .15 short term isn't going to hurt much. I've had rises that happened in a week or so and other times when it took a few months. These happened due to changes in the system, so once I worked it back down the system fell back into a baseline. For example I had about 6 anthias and I fed the crap out of them and didn't realize till a few months later when growth slowed and more algae was showing up. Some short term spike examples were stopping carbon dosing and livestock losses.

I personally dont think that the amount of phosphate present in the water necessarily makes it safer to drop the phosphate more quickly. I thought that at one point but I had a bad experience lowering phosphate too quickly at .1 ppm per day, and that was when my phosphate was .38 ppm so not low at all. Clearly, there are many factors at play here that we dont understand. What works for you may not work for everyone else, as is reefing tradition lol.

Why do you say using gfo in a bag passively is a fruitless endeavor? It just takes longer in a bag than in a reactor, which is what I want. As long as the media doesnt clump it will still work properly.

No it won't...............at least for me it never did and I've tried it more than once.

You may get a small drop at first but unless you have water flowing through the bag you aren't going to get much of a consistent change that will hold. I have had a bag sit below high flow skimmer outputs and that works. Just putting a bag in the sump is very inefficient. The other problem is that without the flow/movement the bag will get covered in bacteria fast and just clog it up from doing anything.

A little confused here because you say it never worked for you but then you say you had a bag sit below high flow skimmer output and that works. Regardless, it has worked for me on several occasions, too well. I always hang mine in front of my skimmer output, lightly tumbling. Like i said previously, if it doesn't clump it will still work properly IME.. I am not concerned about what is the most efficient, or else i would have started with just dosing lanthanum chloride.

I have had corals pale when I've dropped phosphate faster that .1 ppm per day, so .15 ppm in 6 hours concerns me. Maybe since the levels are so high now it wouldnt stress them out as much, I dont know.

If you're going from .15 to .05 that can be problematic, but from the higher levels it's not a problem. I've gone from .25 to .13-.15 and everything was fine.

Again my experience has not been the same. For my tank the rate of reduction is what appears to matter. Good to know it worked that way for you though, maybe it will for me this time, who knows.

My issue has more been guessing when the media is exhausted since my test kit jumps from .5 ppm to .3 ppm. You can see shades in between but it's a guessing game until I get to < .3 ppm.

You need to use a Hannah 736 to really know where you're at. It isn't that important to get perfect accuracy but consistency in readings. There isn't a reason to split hairs and excessively test when doing something like this.
Keep in mind the .15 is just a working target........if you went down a bit more it's not a cause for alarm.

I don't mess with trying to drop low ranges. If my tank readout was .15 I wouldm't mess with it but just monitor. If over weeks or months it's worked up higher then I would do something. People get in trouble trying to micro manage every 100th of a ppm at lower levels.

I am not a fan of the Hanna ULR anymore. I thought I was, in fact i thought everything else sucked and it was the only one i would use, and then i found out how inconsistent and inaccurate it can be. It is also a pain in the butt to use. I certainly dont want to get into a debate on that though. NYOS has been 100% consistent and accurate with my phosphate standard solutions and ICP, the only issue is that i have to guess anything between .5 and .3, but thats really not a big deal to me since i want it lower than both. Yea i dont play with the low ranges either, .1-.2 im happy. a little higher or lower im good too.

 

[Reefahholic]

It's at .5 ppm not >1 ppm, but still, even at that concentration I'm pretty sure its exhausting in a few days. My problem is my test kit wont confirm changes of less than .1 ppm in this high range and thats about as fast as I want to bring it down per week. So I'm trying to see if there's a way to estimate exhaustion relatively accurately.

If I double the amount of gfo I'm concerned I'll have issues because I've stressed corals with that same amount in a bag before. It also may exhaust equally as fast just pull it down quicker so no benefit to me.

LC or large water changes (I dont want to do water changes for several reasons) seem like better options, but I'm just trying this more subtle approach first. Besides slowed growth and a hit to coloration on some acros I'm seeing no ill effects, so no rush at this point.

You can test the water exiting the reactor and see if it’s testing lower than that entering. If so, the GFO has not depleted yet.

Best of luck!

 

[BigJohnny]

You can test the water exiting the reactor and see if it’s testing lower than that entering. If so, the GFO has not depleted yet.

Best of luck!

Thanks for the suggestion but I am using a media bag not a reactor.

 

[Big E]

"A little confused here because you say it never worked for you but then you say you had a bag sit below high flow skimmer output and that works. "

Passively putting a bag in the sump is different than having 2-300g gallons of Skimmer output flushing over a bag of GFO

Regardless, a reactor is going to be more efficient and is not a danger if used properly.
.....half the recommended amount of GFO and low flow.

I'm just trying to help you and others that may read this as it has worked well for many people without losses.

 

[BigJohnny]

"A little confused here because you say it never worked for you but then you say you had a bag sit below high flow skimmer output and that works. "

Passively putting a bag in the sump is different than having 2-300g gallons of Skimmer output flushing over a bag of GFO

Regardless, a reactor is going to be more efficient and is not a danger if used properly.
.....half the recommended amount of GFO and low flow.

I'm just trying to help you and others that may read this as it has worked well for many people without losses.

Of course in front of the skimmer output and just sitting in a corner are different, you can also place under a drain as well. It certainly doesn't need to be in a reactor to work properly.

Yea, a reactor is more efficient, but that's not always the goal and it comes with more risks. I appreciate the suggestion and that your trying to help others but you keep dismissing the possibility that peoples tanks could see negative effects using the technique you mentioned. It's not guaranteed safe imo, at all. I think we can probably agree to disagree at this point. I dont want to argue about this anymore, not why I created the thread.

It does sound like a much safer way to run a reactor though and I appreciate the suggestion and summary of your experiences. Maybe I'll end up trying it at some point and if so I'll report back.

Thanks

 

[Brew12]

It does sound like a much safer way to run a reactor though and I appreciate the suggestion and summary of your experiences. Maybe I'll end up trying it at some point and if so I'll report back.

I have found a reactor to be a much safer way to lower PO4. My very first tank wipe came from putting too big of a bag of GFO into a filter sock.

Now, I run GFO in a reactor with a dedicated pump and a throttle valve. When I need to run it, I plug it in with flow throttled back around 50% for an hour or two then sample the reactor effluent. I'll adjust it as needed to keep the reactor outlet between 0.02 and 0.04ppm. I like my tank around 0.06ppm. This way I never worry about stripping too much out too quickly and I only need to change my GFO when it is exhausted. This has saved money on less frequent GFO changes and has allowed me to stabilize my PO4.

 

[Brew12]

That's actually not true, GFO will release phosphate back into the water if its "exhausted" and the surrounding water is lower in phosphate. That is a fact, I am just not sure how big the difference needs to be for that to happen.

I wish more people were aware of this. The same phenomena happens with GFO as happens in our substrate. If the water is lower in PO4 than the substrate, PO4 will leach into the water. If PO4 in the water is higher it will be obsorbed by GFO and our substrate.

 

[BigJohnny]

I have found a reactor to be a much safer way to lower PO4. My very first tank wipe came from putting too big of a bag of GFO into a filter sock.

Now, I run GFO in a reactor with a dedicated pump and a throttle valve. When I need to run it, I plug it in with flow throttled back around 50% for an hour or two then sample the reactor effluent. I'll adjust it as needed to keep the reactor outlet between 0.02 and 0.04ppm. I like my tank around 0.06ppm. This way I never worry about stripping too much out too quickly and I only need to change my GFO when it is exhausted. This has saved money on less frequent GFO changes and has allowed me to stabilize my PO4.

Your issue was that you put it in a filter sock, not that you ran it in a bag instead of a reactor. It probably got pulverized.

Glad the new method is working for you!

 

[BigJohnny]

I wish more people were aware of this. The same phenomena happens with GFO as happens in our substrate. If the water is lower in PO4 than the substrate, PO4 will leach into the water. If PO4 in the water is higher it will be obsorbed by GFO and our substrate.

Yes most people dont know that. In fact on bulk reef supply someone asked that question under one of their gfos and they responded saying it would not release under normal aquarium conditions. Maybe the difference in concentration has to be much larger than we think, not sure. That was one of the things I was hoping randy would provide clarification on and why i am concerned about pulling it before its exhausted in the first place.

 

[Brew12]

Your issue was that you put it in a filter sock, not that you ran it in a bag instead of a reactor. It probably got pulverized.

Glad the new method is working for you!

Flow through the filter sock was low enough that it wasn't the issue. It was completely user error. I added way too much, in part because I believed people when they said it wouldn't be very effective if it wasn't in a reactor. Scared me away from using GFO again until I could devise a way to control it better. So now I use the reactor, not to make it more effective, but to make it more controllable. I feel it can be dangerously effective in any manner it is added to a tank.

 

[BigJohnny]

Flow through the filter sock was low enough that it wasn't the issue. It was completely user error. I added way too much, in part because I believed people when they said it wouldn't be very effective if it wasn't in a reactor. Scared me away from using GFO again until I could devise a way to control it better. So now I use the reactor, not to make it more effective, but to make it more controllable. I feel it can be dangerously effective in any manner it is added to a tank.

Ah ok just added too much. Yea that's what I'm saying it can be dangerous no matter how you use it, ime. Interesting thought on it being more controllable in a reactor, never looked at it like that.

I would probably try what you guys are suggesting if I dont have success in the bag but I don't feel like dropping $80+ on a decent reactor +pump, especially when I have 1 liter of seaklear LC in my garage, iv feed bags, and 5 micron filter socks......

I've only used lanthanum to pull phosphate out of pukani in a brute but it was incredibly effective and easy. I've been doing some research on how to calculate how much phosphate you will remove by dosing x amount etc so I think I'll try that. I know some people dont worry about the precip but I do so will be dropping a diluted solution over 12 hours into a 5 micron filter sock aiming to drop po4 by no more than .03-.05 per use, with several days in between each use. If I go that route that is.

You ever tried LC?

 

[Brew12]

Ah ok just added too much. Yea that's what I'm saying it can be dangerous no matter how you use it, ime. Interesting thought on it being more controllable in a reactor, never looked at it like that.

I would probably try what you guys are suggesting if I dont have success in the bag but I don't feel like dropping $80+ on a decent reactor +pump, especially when I have 1 liter of seaklear LC in my garage, iv feed bags, and 5 micron filter socks......

I've only used lanthanum to pull phosphate out of pukani in a brute but it was incredibly effective and easy. I've been doing some research on how to calculate how much phosphate you will remove by dosing x amount etc so I think I'll try that. I know some people dont worry about the precip but I do so will be dropping a diluted solution over 12 hours into a 5 micron filter sock aiming to drop po4 by no more than .03-.05 per use, with several days in between each use. If I go that route that is.

You ever tried LC?

I haven't tried it before, so no help there. Sounds like you have everything you need to be successful with it though!

 

[BigJohnny]

I haven't tried it before, so no help there. Sounds like you have everything you need to be successful with it though!

I think so, never done it with livestock in the water though so scares me a little.

Luckily I just tested my phosphate and it's down to .4ppm after only switching it out once over the last week in a half, so far so good. Definitely getting used quickly but it's working in the bag, just slowly, but that's what I want. We will see if it can keep up as I bring it down to .1-.2. I'm using 10 tablespoons instead of recommended 27 so still very conservative.

Btw what reactor/pump/valve do you use?

 

[Brew12]

I think so, never done it with livestock in the water though so scares me a little.

Luckily I just tested my phosphate and it's down to .4ppm after only switching it out once over the last week in a half, so far so good. Definitely getting used quickly but it's working in the bag, just slowly, but that's what I want. We will see if it can keep up as I bring it down to .1-.2. I'm using 10 tablespoons instead of recommended 27 so still very conservative.

Btw what reactor/pump/valve do you use?

I use the BRS deluxe reactor with the Cobalt MJ1200 pump. I have their basic reactor for my GAC. No real preference between the two.

 

[Gareth elliott]

I have 2 different reactors,
An Aquatop that came with a pump. Its ok, a little tough to open at times.

The other is a small somatic reactor with a cobalt mj pump, much easier to open. The aquatop(i think the changed company names recently?). Is not bad for the low price been going a year with no pump problems just a little more time spent opening it when i need to.

Somatic one came free with a purchase of media at the time. Much simpler design.