What are the actual observed drawbacks of long-term GFO use?

[Dkeller_nc]

One add on to the comment about duplicating natural conditions. This sometimes gets interpreted by reefers that they need to have concentrations of dissolved inorganic nutrients similar to what's observed on natural reefs. For nitrate and phosphate, that's very nearly zero (not actually zero, but well below what our typical hobbyist kits can measure).

The problem with trying to duplicate these conditions is that a reef is a lot like a rainforest; there's a very high concentration of nutrients in both a rainforest and on a reef, but those nutrients are contained within living things. If you were to measure soil nitrogen, phosphorus and potassium (NPK) in rain forest soil, you'd find that there's very little. Instead, there's an enormous amount of nutrients bound up in vegetation that gets rapidly recycled by fungi, allowing lush plant growth.

Similarly, on a reef there's very little in the way of dissolved inorganic nutrients, but an enormous amount of nutrients bound up in plankton that the corals make use of. We can't duplicate that in our reefs, so we generally aim for a much higher concentration of inorganic phosphate and nitrates that our corals can make use of.

 

[WallyB]

Here are my thoughts, observations, and current method of GFO Use + ADDICTION!

Over the years, I had high Phosphates. No issues in my Mixed/LPS Tank, with Phosphates at high as 0.4-0.6 ppm. Nitrate also sky high 40-50pm+. Best growth I've ever had but that was under Metal Halaide lighting.

As always for years, my SPS only tank suffered in every possible way. Tinkering (No Stability) was the main culprit.

I did try Phosban, bulk Granular GFO, and dabbled with RhowaPhos.

• Past problem was I would load up the Reactor and forget about it for months. Then a reload would just cause another Phosphate Down Spike.
• Worst experience was PhosBan since it seem to just not work at getting my Phosphates down.
  • It could have been just my Rock leaching out phosphates slowly, and I never tried long enough to reach stable low P.

Then I learned from a experinced/succesful SPS manager at a store, to be consistant with GFO and small amounts.

My routine Last 6-8 months:

• I change my RhowaPhos Media EVERY TWO Weeks. Small Quantity (1/4 cup for a 110G SPS only tank. All frags)
• I run the Two Little Fishies reactor at just a trickle (This extends the life of the GFO, and reduces a high drop in P while it's new Media, and then results in a rise with expired GFO)
• Fish load is medium and I feed about 4 cube of frozen a day, plus some pellets and flake
• Over time I got my Phosphates stable at around 0.1 ppm and that seems to be the sweet spot for my SPS corals

For replenshing Trace Elements:

• I switched from 20% Monthy water changes to 1% daily
• I dose ESV two Part every hour
  • I test weekly Calcium, Alkalinty to adjust Dosing.
  • I do the odd test on Phosphates, and Magnesium and each time everything is in check.

KNOCK on WOOD, this is the longest I've ever been succesfull with my SPS Frags (Color, Growth and PE). No bleached SPS for a long time!! (Used to be every few weeks I would lose an SPS frag, leading to a vicious cycle of restocking, and emptying my wallet)

THE ONLY DOWNSIDE of using GFO long term that I can think of is you get HOOKED on using it. What I mean is if you achieve Proper P levels (what ever they are) and P stability using GFO regularily in low quanties like I have, and it's use has resulted in Tank Coral Success. I fear stopping it's use. I fear that I may not be able to keep P stable with my current fish load and feeding. It may result in me returning back misserable SPS upkeeping conditions. (This could be said of any products we use and achieve good results).

 

[TheDragonsReef]

Ive been running gfo or similar phosphate material for atleast 4-5 years 24/7. No noticeable problems even with regular icp tests

 

[Emerson]

I ran a separate GFO reactor for about 1 year and a half before I completely bottomed out PO4. About the same time my tank had matured enough where the NO3 level was also very, very low, at times unmeasurable. This lead to (in my estimation) a cyano bloom followed by a dino crash. Also leading up to this, my corals (SPS/LPS) had poor color and little growth.
It wasn't until after I (hesitantly) took out the GFO and let the PO4 level rise and added NO3 with Brightwell NeoNitro to keep measurable levels of both that consistently that I finally got past my 10 month battle with those nightmares. Now I run a single reactor with 2/3 cup Carbon 1/3 cup GFO and change it out every 2-3 weeks. I still have to add NeoNitro, but my PO4 stays consistently low, but not too low, ~0.05-0.02 ppm. If PO4 levels climb much over 0.10 ppm I dose Brightwell Phosphat-E to get to the nutrient level that works for me.

 

[Maokin]

I too watched this video with Lou. I have been using GFO (BRS high capacity) since the beginning (2 years) as needed in my tank RSR250. Recently ICP came back with high Iron which was the last straw for me and GFO. I used a BRS mini reactor with my GFO to get it to tumble but perhaps I had too much flow. I did notice that near the output of the reactor some fine GFO like dust and the GFO in the reactor also showed signs of being ground down. I changed over to using bio pellets for like a week as a form of carbon dosing but that ticked off my duncan and goniporia. Only after running carbon and 2-3 weeks later is the goni finally opening back up. The ducan was much quicker to open only after 3-5 days.

PO4 is 0.10 last i checked might try the pellets again or phosphate-e. Everyone always says GFO doesn't leach iron into your tank but i am not convinced with my experience. Also with GFO striping out other useful things, I won't be using it for a long time.

 

[David S]

Until about a month ago, I had been using Rowaphos 24/7 for more than 10 years in a TLF Phosban Reactor.
It kept my Phosphates between .02 - .05 for 2 - 3 months, before replacing.
Numerous ICP tests indicate no apparent issues.
I had tried Chaetomorpha and various carbon dosing but they came up short in checking PO4 in my tank.
If anyone is interested in using GFO in a reactor, I'd recommend the following.
The GFO tend to initially drop the PH and alkalinity in the tank so you would want to soak it before running it in the reactor.
When you run it in the reactor, you want to make sure the GFO is at least slightly tumbling. If it is not, the GFO will "channel" and become a solid mass and it will no longer take out any phosphate.
Having said this, you may ask why I haven't used the GFO for the last month.
It is because I have found a successful way of growing macroalgae in my tank.
Why have I been able to do it this time? It's due to my current dosing of nitrates in my tank.
The history of my tank has been to have low NO3; in the range of 0.25 - 3.0 PPM and left unchecked; high Phosphate levels.
In the past, when I tried using Chaeto, I initially got explosive growth, presumably due to whatever NO3 was in my system. But once that was absorbed by the Chaeto it would eventually decline.
It occurred to me that since, I had begun dosing NO3, several months back, to improve my LPS growth, that it may allow me to grow macroalgae on a consistent basis.
So far, that is exactly what is happening. The added Nitrates are feeding the macro and it's growth is keeping the PO4 at a very low level.
Finally, I should mention, that instead of Caulerpa or Chaeto, I switched to Red Ogo, which is a form of Gracilaria. It grows like a weed.
For this I have to thank a fellow Reefer, named Aaron, who was a recent guest on Devin's "Reefdudes" channel on Youtube.

 

[foshizzle]

I think GFO is a mistake. Low PO4 can crash your tank and bleach your corals. I was on the ULN bandwagon once but now I have trouble keeping PO4 high enough (0.03). I feed clean, cheap, frozen seafood - fish are fat and corals look great. IMO prepared fish foods fuel the GFO market.

 

[Big E]

Until about a month ago, I had been using Rowaphos 24/7 for more than 10 years in a TLF Phosban Reactor.
It kept my Phosphates between .02 - .05 for 2 - 3 months, before replacing.
Numerous ICP tests indicate no apparent issues.
I had tried Chaetomorpha and various carbon dosing but they came up short in checking PO4 in my tank.
If anyone is interested in using GFO in a reactor, I'd recommend the following.
The GFO tend to initially drop the PH and alkalinity in the tank so you would want to soak it before running it in the reactor.
When you run it in the reactor, you want to make sure the GFO is at least slightly tumbling. If it is not, the GFO will "channel" and become a solid mass and it will no longer take out any phosphate.
Having said this, you may ask why I haven't used the GFO for the last month.
It is because I have found a successful way of growing macroalgae in my tank.
Why have I been able to do it this time? It's due to my current dosing of nitrates in my tank.
The history of my tank has been to have low NO3; in the range of 0.25 - 3.0 PPM and left unchecked; high Phosphate levels.
In the past, when I tried using Chaeto, I initially got explosive growth, presumably due to whatever NO3 was in my system. But once that was absorbed by the Chaeto it would eventually decline.
It occurred to me that since, I had begun dosing NO3, several months back, to improve my LPS growth, that it may allow me to grow macroalgae on a consistent basis.
So far, that is exactly what is happening. The added Nitrates are feeding the macro and it's growth is keeping the PO4 at a very low level.
Finally, I should mention, that instead of Caulerpa or Chaeto, I switched to Red Ogo, which is a form of Gracilaria. It grows like a weed.
For this I have to thank a fellow Reefer, named Aaron, who was a recent guest on Devin's "Reefdudes" channel on Youtube.

Red ogo uptake is around 50/50 and an excellent choice.
I think I would try to mix in some others as well. Ulva is another good choice.
Using just one type of macro isn't perfect but a better option than chaeto.

Calerpa always worked well for many reefers 15 or so years back but if it got into the system it was tough to eradicate. It would also tend to dominate and out grow the other algae. Another issue is that it would go asexual. With all that, it fell out of favor.

Imo, if more people had a more dedicated algae filter with mixed macros in a larger tank size than a sump compartment you could probably use just that and have no need for a skimmer.

 

[Randy Holmes-Farley]

I too watched this video with Lou. I have been using GFO (BRS high capacity) since the beginning (2 years) as needed in my tank RSR250. Recently ICP came back with high Iron which was the last straw for me and GFO. I used a BRS mini reactor with my GFO to get it to tumble but perhaps I had too much flow. I did notice that near the output of the reactor some fine GFO like dust and the GFO in the reactor also showed signs of being ground down. I changed over to using bio pellets for like a week as a form of carbon dosing but that ticked off my duncan and goniporia. Only after running carbon and 2-3 weeks later is the goni finally opening back up. The ducan was much quicker to open only after 3-5 days.

PO4 is 0.10 last i checked might try the pellets again or phosphate-e. Everyone always says GFO doesn't leach iron into your tank but i am not convinced with my experience. Also with GFO striping out other useful things, I won't be using it for a long time.

I don't know why you'd have high iron.

I used GFO and also dosed iron, and still it was undetectable in my tank.

 

[Randy Holmes-Farley]

I think GFO is a mistake. Low PO4 can crash your tank and bleach your corals. I was on the ULN bandwagon once but now I have trouble keeping PO4 high enough (0.03). I feed clean, cheap, frozen seafood - fish are fat and corals look great. IMO prepared fish foods fuel the GFO market.

Doesn't that mean "overuse" of any phosphate export mechanism "is a mistake"?

Why would appropriate use of GFO that leads to appropriate target levels of phosphate be a mistake?

 

[foshizzle]

Doesn't that mean "overuse" of any phosphate export mechanism "is a mistake"?

Why would appropriate use of GFO that leads to appropriate target levels of phosphate be a mistake?

Well, sure. If you are willing to test every few days, schedule regular replacement of media, tinker with your reactor, etc. go for it. I mean that I dont find the risks and hassle of using GFO to be worth it. I'm mostly acros and IMHO my the corals dont care that much when PO4 is a little higher than "optimum" - they definitely show stress when I have let PO4 drop too low. I'm satisfied getting numbers close to "optimum" with skimming and some macroalgae

 

[JayinToronto]

Red ogo uptake is around 50/50 and an excellent choice.
I think I would try to mix in some others as well. Ulva is another good choice.
Using just one type of macro isn't perfect but a better option than chaeto.

Calerpa always worked well for many reefers 15 or so years back but if it got into the system it was tough to eradicate. It would also tend to dominate and out grow the other algae. Another issue is that it would go asexual. With all that, it fell out of favor.

Imo, if more people had a more dedicated algae filter with mixed macros in a larger tank size than a sump compartment you could probably use just that and have no need for a skimmer.

I've often wondered if some macro's consumed nitrates and phosphates at different ratios. You said that Red Ogo is 50/50. Where is this information from? Do you have any ratio uptake info on the other macros (chaeto, hair, caulerpa)?

 

[revhtree]

Interesting thread!

 

[Big E]

I've often wondered if some macro's consumed nitrates and phosphates at different ratios. You said that Red Ogo is 50/50. Where is this information from? Do you have any ratio uptake info on the other macros (chaeto, hair, caulerpa)?

There are many academic papers with uptake ratios. Here is one I had on file but there are many others if you do a search. This one had gracilaria much more efficient at P04 uptake. Read the whole article it's interesting.

Using Macroaglae as a bioremediator near nutrient-rich estuaries

dspace.carthage.edu

And another I had on file---

(PDF) Nitrogen-versus phosphorus-limited growth and sources of nutrients for coral reef macroalgae

PDF | Recent investigations of nutrient-limited productivity in coral reef macroalgae have led to the conclusion that phosphorus, rather than nitrogen,... | Find, read and cite all the research you need on ResearchGate

www.researchgate.net

In this table is where I may have remembered the 50/50 ratio

The biggest thing to draw from any of this is if you go the macro algae filter route, educate yourself and don't just be a sheep. From most of the info I gathered chaeto creates the worst limited factor with nitrates and also the least efficenent overall. It's why I suggest to people use a mix.

To me if you have the room it would make a lot of sense to create a true refugium with a mix of algae species and also a place for pod, worms, ect. to proliferate and add planktonic diversity to your system.
----------------------------------------------------

I don't favor algae filters because they suck up a ton of elements, release toxins and doc. They are coral killers as well a competitors in the wild when they can prosper.

There is a ton of academic/scientific literature on this as well. I'm not going to get too far into it as this subject is probably best for another thread and will also cause a ton of debate which I don't have any desire to get into.

I just mention it to explain why I prefer to use GFO for P04 reduction.

 

[Randy Holmes-Farley]

Well, sure. If you are willing to test every few days, schedule regular replacement of media, tinker with your reactor, etc. go for it. I mean that I dont find the risks and hassle of using GFO to be worth it. I'm mostly acros and IMHO my the corals dont care that much when PO4 is a little higher than "optimum" - they definitely show stress when I have let PO4 drop too low. I'm satisfied getting numbers close to "optimum" with skimming and some macroalgae

lol


I used GFO 24/7 for many years and NEVER had an issue, and very rarely tested for phosphate (much less than once a year). I also used skimming, macroalgae, GAC, and organic carbon dosing at the same time.

IMO, it is a matter of using it and all methods properly.

 

[Randy Holmes-Farley]

I've often wondered if some macro's consumed nitrates and phosphates at different ratios. You said that Red Ogo is 50/50. Where is this information from? Do you have any ratio uptake info on the other macros (chaeto, hair, caulerpa)?

Different macroalge can have different uptake ratios, as noted above, and the ratio can depend on the water levels of N and P. I do not have data for red ogo (GRACILARIA PARVISPORA).

Here's a pdf with a bunch (same article as above). Look at table 2. It shows what you are asking about, with caulerpa much higher in N relative to P compared to other macroalgae they tested.

Wayback Machine

 

[Mrtakeoff53]

I tried not using GFO but my PO4 would climb to 0.6 or so and I had serious coral damage and death. I found a balance with PO4 at .06-.1 by running my GFO for only 12 hours a day. I have it hooked up to my APEX and it runs from 5 am to 5 pm. It’s what works for me. Maybe this could be an alternate solution to those running it 24/7 who have problems with trace elements and PO4 being too low.

 

[schuby]

I'm not trying to duplicate the ocean as much a having a thriving colorful acropora system.

The natural comments are so lame.............large chaeto balls don't grow within a small area next to acropora. Have you ever fed your fish pellets/flakes, used chemicals? Do you use synthetic salt for your aquarium?

Alage filters take out way more elements in the water than GFO does. Algae directly competes for these same elements that corals need. Why do you think there a dozens of fish and inverts that naturally keep all algae mowed down to nothing over a reef.

I don't use algae filters........a lot of times you get to a point of nitrate limitation and then you have to dose nitrate. Chaeto only filters take out a ratio of 100-1 so you can still have a problems with P04.

I would like to eliminate GFO but find it hard to find substitutes that work as well. My second choice is carbon and bacteria dosing and I'm looking to find the right combo to keep both N03 and Po4 in check to my satisfaction.

A lot of people like algae filters and that's fine but I consider them more harmful than good.

If you don't use algae filters, do your corals keep your Nitrate in check or do you use another Nitrate-removal method?

 

[schuby]

This was my experience with GFO. Maybe it will be insightful to someone.

About 7 months after starting my current tank, a 150gal with 150-200 lbs of dry (aragonite) rock, my large chaeto ball died, flooding my tank with Phosphate and Nitrate. I'd never run macro-algae before and didn't know to dose additional iron, nor did I know what chaeto looked like when it was dying.

To lower my PO4, I purchased a GFO reactor and Rowaphos. The reactor maxed at two cups of media. I went with 1 cup. The phosphate would lower in my tank by about 0.1 ppm over a month, running 24x7. I'd change the media each month when PO4 started to rise instead of fall or stay steady. I eventually got PO4 down to around 0.2 and later stopped running GFO to see if my SPS frags and chaeto would keep it down.

Fast forward 1.5 years to now. I'd not run GFO for about a year and chose to run it again as my PO4 had drifted up to 0.57ppm. I reinstalled the GFO reactor with the same 1 cup of Rowaphos. I measured PO4 after 3 days (my normal, twice-a-week measurement) and PO4 was down to 0.21 ppm. I turned GFO reactor off for a few days and am now running it only 12 hours a day. I'll adjust it as necessary to keep PO4 low but not zero.

My point is that GFO on a young tank, started with dry rock, with no coralline behaves much differently than a mature tank with coraline-covered. mature rocks. A simple, gross estimate is 30x times faster removal now vs 1.5 years ago. I'm guessing it's due to far less bare rock for the PO4 to bind with.

TLDR: GFO seems to remove PO4 much faster in a tank with coraline-covered rock than in a tank without coralline-covered rock.

 

[ReefGeezer]

OOPS! Wrong Thread. Sorry.