To GFO, or not to GFO, THAT is the question!

[GoPitt88]

I have a 55 gallon mixed reef tank with 15 various types of coral. Been running now for 2 years. I started using GFO about a year ago thinking that it would help reduce the amount of algae, but I still need to scrape the glass every 2 or 3 days. Other than that, I have no algae issues whatsoever. But I'm running a very clean system with 0.00 ppm Phosphates and between 0 and 2 ppm nitrates. Is that OK for my coral? If I stop running GFO, won't my algae take off? All but one of my coral look good, except for a new war coral. It's eyes are still bright green, but the edges are getting very pale. Please advise. Thanks! [emoji16]

 

[bif24701]

Algae growth isn't directly linked to the amount of NO3 and PO4 in your system. I keep algae growth down with some vinegar dosing and a chaeto refugium.

Zero PO4 isn't great for coral but you say there is daily algae growth in the glass so the actual number is higher. How do you test PO4? Are your coral brightly colored and growing? Pale corals can mean that you have low nutrients (NO3 & PO4).

I keep my PO4 down with water changes and the chaeto, but I have to add some Nitrates.

 

[Tariq]

There’s no straightforward answer to this, it all depends whether or not your system actually needs gfo.

I will share my experience, I used to use gfo, I have light bioload and decided to take it off and I am glad I did that. One less thing to worry about and buy.

With a good skimmer, macro algae and good husbandry practice, gfo is not needed. I have sps corals and everything looks fine.

If you want to go this route, take it off slowly. There’s absolutely no need to have zero nutrients. Some PO4 and nitrates are healthy and required.

Tests are just one side of the hobby. Always look at the health of corals before tweaking anything. Only make changes if test results are off plus corals are acting up. No point in adding phosphates and then using gfo.

 

[jda]

Nobody has zero N and P, not even the ocean - they might test that way, but be assured that you have some.

I agree - take it off slowly and observe. People used to do better with this before test kits got so good, but you will get to where just taking a look at a reef will be like those people in The Matrix reading the green characters dripping down the screens.

 

[GoPitt88]

Algae growth isn't directly linked to the amount of NO3 and PO4 in your system. I keep algae growth down with some vinegar dosing and a chaeto refugium.

Zero PO4 isn't great for coral but you say there is daily algae growth in the glass so the actual number is higher. How do you test PO4? Are your coral brightly colored and growing? Pale corals can mean that you have low nutrients (NO3 & PO4).

I keep my PO4 down with water changes and the chaeto, but I have to add some Nitrates.

I use a Hanna Checker. With regards to coral color, I'd say they are on the dull side, but I really can't compare to what they should be since this is all I know. I may try slowly going GFO-less and see what happens. [emoji846]

 

[GoPitt88]

Nobody has zero N and P, not even the ocean - they might test that way, but be assured that you have some.

I agree - take it off slowly and observe. People used to do better with this before test kits got so good, but you will get to where just taking a look at a reef will be like those people in The Matrix reading the green characters dripping down the screens.

Here are my test results:

[emoji13]

 

[GoPitt88]

Any others with advice, or do you agree with what's been said already?

 

[reeferfoxx]

How is your clean up crew responding to the algae?

 

[Big E]

If you're happy with growth and color of your acros I wouldn't change a thing.

I'd focus more on flow(too much) or light being too intense for the war coral...........try moving it.
Is this new war coral on a rock? If you just have it laying in the sand it's edges can be bothered.

 

[SuperDragon]

It's a balancing act but your numbers good good on paper, maybe feed more food.
I wouldn't mess with a good thing. Overdosing on GFO can kill and if you decide to just go slow. Same goes for a cleanup crew, too many and they starve and die.

 

[GoPitt88]

If you're happy with growth and color of your acros I wouldn't change a thing.

I'd focus more on flow(too much) or light being too intense for the war coral...........try moving it.
Is this new war coral on a rock? If you just have it laying in the sand it's edges can be bothered.

The war coral is on a plug, now on the sand. It was previously halfway up on the rocks. It's definitely still alive. Just trying to see if it was getting too much light. I have Kessil A360WE Tuna Blues that max at 90% intensity mid day. That's OK for all of my other coral.

 

[2Wheelsonly]

Tinkering with things that are not broken leads to dead coral. I speak from much experience; threw my GFO in the trash and stopped chasing po4. Unless you have hair algae growing everywhere and your corals are brown I wouldn't change a thing. IF you have green hair algae and brown corals then GFO is a terrible fix, as you most likely have husbandry process issues and your time is best spent on fixing that.

As mentioned, you're going to be cleaning glass regardless if you have low or high nutrients. Using GFO because you have dirty glass is like using a hazmat suit to clean a toilet after someone took a $*%# in your bathroom.

 

[GoPitt88]

Using GFO because you have dirty glass is like using a hazmat suit to clean a toilet after someone took a $*%# in your bathroom.

Obviously, you've never met my 14 year old step-son [emoji90]

 

[GoPitt88]

Tinkering with things that are not broken leads to dead coral. I speak from much experience; threw my GFO in the trash and stopped chasing po4. Unless you have hair algae growing everywhere and your corals are brown I wouldn't change a thing. IF you have green hair algae and brown corals then GFO is a terrible fix, as you most likely have husbandry process issues and your time is best spent on fixing that.

Thanks for the advice [emoji106]

 

[Big E]

The war coral is on a plug, now on the sand. It was previously halfway up on the rocks. It's definitely still alive. Just trying to see if it was getting too much light. I have Kessil A360WE Tuna Blues that max at 90% intensity mid day. That's OK for all of my other coral.

A lot of favias need very little light. I've had to shade a few that I have or they'll be pale or not have good coloration. Try putting it in a shaded area or place it at an angle so it isn't getting direct light.