Can GFO really remove phosphates this quickly?

[Oregon Grown Reef]

My phosphates went through the roof recently!!! I tested and it was at 0.396ppm! I couldn't believe it since I used to dose phosphate in this tank. I stopped dosing and monitoring awhile ago because all of my corals minus the zoas and a couple of blastos died from a crash in July/August which nearly caused me to leave the hobby. I know that water changes aren't particularly effective against phosphates and I had an old reactor laying around, so I threw in some gfo and a sicce syncra silent 1.5 and let it run for 1 day before testing again. I've never used gfo before, so I was a bit nervous at first and I wasn't 100% sure how long it was going to take to remove the phosphates even after some research. It took me a few tries to get the flow where I was happy with it. I tested it again today and it was at 0.08!!! That can't be right, can it? I followed the instructions on the package and used 1.5 cups for 50 gallons. I ran it for another few hours after the test before shutting it off as I wanted it closer to 0.04. I like to do my testing at the same time of day so I can get a consistent trend, so I'll be testing again tomorrow around 1-3pm. After doing some reading, people are saying that it takes a lot of gfo to remove high amounts of phosphate. I would have considered what I had ridiculously high, and maybe I'm wrong about that, but I also expected it to take a week for it to remove that much phosphate and much more media as well. Does something sound wrong here? Also, will removing this much phosphate at once have an effect on any other elements such as Alk, CA, Mg, trace/minor? My nitrates were at 25 yesterday as well, so I'll be doing another series of water changes to bring those down closer to 5.

Any and all help is greatly appreciated!

 

[outhouse]

Does something sound wrong here?

Nope

Also, will removing this much phosphate at once have an effect on any other elements such as Alk, CA, Mg, trace/minor?

Not really.

 

[Oregon Grown Reef]

Nope

Not really.

How is it that people run gfo full time on their tanks if it works this efficiently? Or do they only run it when the phosphates are too high?

 

[outhouse]

Its the amount you or I run, that matters. I run a half a cup on a 300g system. I leave it in the whole month. I never test, just view corals and notice how much or how little build up on glass i get. I dont run HC gfo, I probably should.

I also do 100g monthly water changes at the moment.

 

[2una]

Also, will removing this much phosphate at once have an effect on any other elements such as Alk, CA, Mg,

Yes, check your alk

 

[Oregon Grown Reef]

Its the amount you or I run, that matters. I run a half a cup on a 300g system. I leave it in the whole month. I never test, just view corals and notice how much or how little build up on glass i get. I dont run HC gfo, I probably should.

I also do 100g monthly water changes at the moment.

High capacity is so expensive though at nearly double the cost and if it works as well as this, then I'm definitely just going to use a lot less for now on.

 

[outhouse]

High capacity is so expensive though at nearly double the cost and if it works as well as this, then I'm definitely just going to use a lot less for now on.

right! I saw some labeled as such on ebay, but it was that light brown stuff, so you know its just regular.

Did find some regular gfo for 2lbs for 35 bucks.

 

[Oregon Grown Reef]

Yes, check your alk

Thank you, sir! Alk dropped from 8.5-8.6 to 7.9! Not catastrophic, but good to know. I know there's a RHF article on here somewhere, but is that all that I need to be concerned about? Did calcium also take a dive?

 

[gbroadbridge]

My phosphates went through the roof recently!!! I tested and it was at 0.396ppm! I couldn't believe it since I used to dose phosphate in this tank. I stopped dosing and monitoring awhile ago because all of my corals minus the zoas and a couple of blastos died from a crash in July/August which nearly caused me to leave the hobby. I know that water changes aren't particularly effective against phosphates and I had an old reactor laying around, so I threw in some gfo and a sicce syncra silent 1.5 and let it run for 1 day before testing again. I've never used gfo before, so I was a bit nervous at first and I wasn't 100% sure how long it was going to take to remove the phosphates even after some research. It took me a few tries to get the flow where I was happy with it. I tested it again today and it was at 0.08!!! That can't be right, can it? I followed the instructions on the package and used 1.5 cups for 50 gallons. I ran it for another few hours after the test before shutting it off as I wanted it closer to 0.04. I like to do my testing at the same time of day so I can get a consistent trend, so I'll be testing again tomorrow around 1-3pm. After doing some reading, people are saying that it takes a lot of gfo to remove high amounts of phosphate. I would have considered what I had ridiculously high, and maybe I'm wrong about that, but I also expected it to take a week for it to remove that much phosphate and much more media as well. Does something sound wrong here? Also, will removing this much phosphate at once have an effect on any other elements such as Alk, CA, Mg, trace/minor? My nitrates were at 25 yesterday as well, so I'll be doing another series of water changes to bring those down closer to 5.

Any and all help is greatly appreciated!

1.5 cups in 50 g is a LOT of gfo.

I run about 1/2 cup in 75 g and it lasts about a month with a lot of added phosphate (about 8 cubes frozen a day)

 

[Oregon Grown Reef]

1.5 cups in 50 g is a LOT of gfo.

I run about 1/2 cup in 75 g and it lasts about a month with a lot of added phosphate (about 8 cubes frozen a day)

I just followed the instructions. It says 1 cup for every 24 gallons, so I even undersized it according to the package. Glad to know I can use this stuff for years to come now!

 

[2una]

Before you do too many victory laps what's likely happening is you've removed the Po4 from the water but if its been higher level for a while the rockwork & substrate will now leach it back into the water so it will take awhile to work it out of the system.

 

[Oregon Grown Reef]

Before you do too many victory laps what's likely happening is you've removed the Po4 from the water but if its been higher level for a while the rockwork & substrate will now leach it back into the water so it will take awhile to work it out of the system.

It's a barebottom system, so substrate doesn't apply. How long would it have had to have been that high for it to leech into the rocks? It's been a few months at best. I understand rock absorbs large amounts of phosphate and was likely the reason I was dosing phosphate during the early months of the tank, but I thought it would have taken longer than that to saturate the rock to those levels. The plan was already to continue to monitor the levels and deploy gfo when it's needed to bring the levels down over time, but the thread was more pointed towards the effectiveness of gfo.

 

[2una]

It's a barebottom system, so substrate doesn't apply. How long would it have had to have been that high for it to leech into the rocks? It's been a few months at best. I understand rock absorbs large amounts of phosphate and was likely the reason I was dosing phosphate during the early months of the tank, but I thought it would have taken longer than that to saturate the rock to those levels. The plan was already to continue to monitor the levels and deploy gfo when it's needed to bring the levels down over time, but the thread was more pointed towards the effectiveness of gfo.

Ok with no substrate you'll be a step ahead but the rockwork will likely take a while till it equalizes with the water. You'll be able to tell if its doing that by turning the gfo off & test again after a day or so & see if the level rose back up from where it was when you shut it off.

 

[outhouse]

How long would it have had to have been that high for it to leech into the rocks?

A long time, not only that, calcification locks it up where it cant be leached out. So its more of a problem in low PH and ALK tanks. You should get traces, only thing I would be worried about is false readings, but since you used so much it makes that possibility less likely.

 

[homer1475]

I use 3 tablespoons mixed in with my carbon in my 80G.

I can drop phosphates from .2 to .1 in a couple hours. Then maintain them there with only 3 TBSP.

GFO is really powerful stuff, just be aware it doesn't take much, and overuse will not only kill your coral, but also starve your system which brings a whole nother set of issues.

 

[Screwgunner]

I run a algea scubber and my nitrates a phosphates are under the radar. But I had a order of snails come in from cali and some did not make it . That gave me a gha explosion. So I used vibrant for 7 weeks it melted the gha and rendered my algea scubber useless. Phosphates made it to .12 phosgaurd took it to .04 back up to .07 gfo took it down to .well I don't know my algea scubber kick in after 20% water change and its back to undetectable again.

 

[Oregon Grown Reef]

I use 3 tablespoons mixed in with my carbon in my 80G.

I can drop phosphates from .2 to .1 in a couple hours. Then maintain them there with only 3 TBSP.

GFO is really powerful stuff, just be aware it doesn't take much, and overuse will not only kill your coral, but also starve your system which brings a whole nother set of issues.

I'm glad to know I won't have to use so much. I bought a deluxe reactor from brs as I like that it comes with a bleed valve to release trapped air and a ball valve for controlled flow rates. This will allow me to use smaller amounts of gfo without it creating a snow globe.

 

[Oregon Grown Reef]

I'll be updating the thread later today once I've done the next test.

Side note, the Hanna checkers are so nice. The phosphate test takes 6-7 minutes tops and it's an accurate number down to +/- 5ppb. The alk checker is also stupid quick. By the time I read 2una's comment to check alk, I had the answer within minutes.

 

[Oregon Grown Reef]

Okay so phosphates rose to 0.132ppm after shutting it off last night. There is definitely more phosphates bound up. There's quite a bit less gfo now, so I'm going to try running it overnight again to see what the levels are tomorrow. Thanks again for all of the help folks.

 

[Snoopy 67]

Run it 24/7 or you risk fouling water in a container with no flow.
To test if it is exhausted check the tank water & the flow coming out of the unit. Being close or the same means it should be replaced.