To GFO or not to GFO

[HB Fisheye]

Some time ago I tested my phosphate and it was .25 ppm. I decided to get everything ready to run GFO. So I set everything up and started running the reactor. I then tested the phosphate again only to find it was .10 ppm. I know that's a bit high but everything looks happy. So now I'm trying to decide if I should continue to run the reactor or not. I have a total volume of 150 gallons and I put 10 tablespoons in the reactor.

 

[JustAnt]

I just turned off my gfo/carbon reactor since it reduced my phosphates down to zero and I read that zero phosphate is bad for sps. So I would watch your phosphates don’t go to zero.

 

[theMeat]

Do you have a means of phosphate removal, other than gfo or water changes. Like refugium or algae scrubber?

 

[HB Fisheye]

Do you have a means of phosphate removal, other than gfo or water changes. Like refugium or algae scrubber?

I'm currently running a cheato reactor. Doesn't seem to be growing much however.

 

[JustAnt]

Which cheato reactor do u use? Surprised u have phosphates with gfo and a cheato reactor

 

[theMeat]

I'm currently running a cheato reactor. Doesn't seem to be growing much however.

What’s your nitrates?
With phosphate at .1 lack of phosphate is not the cause of cheato not growing.

.1 is not terrible, ideally should be .03-.05.

If it were me, until your realtor starts growing, run gfo till down to .05

Also, check phosphate and nitrates at the same time of day each time. The best time is right before lights come on

 

[HB Fisheye]

Which cheato reactor do u use? Surprised u have phosphates with gfo and a cheato reactor

Sorry I don't recall the brand. It isn't a fancy one. It looks like this https://petoverstock.com/wavereef-a...MI0cSTz9ie4wIVDtRkCh1dLQdxEAQYBiABEgIT5_D_BwE but this isn't it. I'm not currently running GFO just set up to run it.

 

[HB Fisheye]

What’s your nitrates?
With phosphate at .1 lack of phosphate is not the cause of cheato not growing.

.1 is not terrible, ideally should be .03-.05.

If it were me, until your realtor starts growing, run gfo till down to .05

Thanks @theMeat. I was trying to start slow on the GFO. Do you think 10 tablespoons is an ok amount to start?

 

[theMeat]

Thanks @theMeat. I was trying to start slow on the GFO. Do you think 10 tablespoons is an ok amount to start?

You don’t want it coming down more than .02 points a day. If you think it’s coming down faster than that then lower flow/gph through gfo

Gfo works like this...
If you have a lot of phosphate to remove use small amounts and change frequently.
Use larger amounts and remove less frequent if you use it for more stable phosphate.
Because larger amounts will slow down the flow, given you’re using the same pump/gph

What’s your nitrates?

 

[jda]

Go really slow. .10 is 10-20x more than seawater, so lower levels will not bother corals at all, but lowering it quickly is usually a big problem.

I advocate, using very little and changing it often. You have to give the rock and sand time to release the bound-up phosphate back into the water column. If you remove it from the water too quickly, then it will spike down with the GFO, then spike back up when the aragonite releases it's share. The spiking up and down is what is bad.

 

[JPergamo]

I'm mostly anti gfo. Every time I've used it, there have been some downsides like small cyano outbreaks when phosphate gets too low. Ive done it slow over weeks and weeks, and fast with large amounts, the results are usually the same. I like a natural approach of removal from water changes and chaeto. If it is PO4 is exorbitantly high I suppose using it to bring it within a normal high range would be ok but I would advise against stripping it all out of the water. Just my 2 pennies, many use it 24/7 with good results.

 

[theMeat]

I'm mostly anti gfo. Every time I've used it, there have been some downsides like small cyano outbreaks when phosphate gets too low. Ive done it slow over weeks and weeks, and fast with large amounts, the results are usually the same. I like a natural approach of removal from water changes and chaeto. If it is PO4 is exorbitantly high I suppose using it to bring it within a normal high range would be ok but I would advise against stripping it all out of the water. Just my 2 pennies, many use it 24/7 with good results.

You can easily monitor/test for levels. Take off line or lower flow as needed.

Cyano is not going to happen that fast from low p04 alone.

And you’d see a dif in your corals without any testing, and before cyano happened

 

[SPR1968]

Adding rhowaphos to my system in a reactor was the best single thing I have ever done.

I keep phosphate locked down around 0.03ppm so very low and have never had any issues with algae or anything else

You don’t however want zero nitrate and sterile water or that’s when you may run into issues

 

[JPergamo]

You can easily monitor/test for levels. Take off line or lower flow as needed.

Cyano is not going to happen that fast from low p04 alone.

And you’d see a dif in your corals without any testing, and before cyano happened

I forgot to add that my system will not produce a nitrate for whatever reason and both levels would bottom out if not dosing kno3, most likely causing the issues I was referring to. And of course yes the levels need to be monitored while using gfo.

 

[HB Fisheye]

You don’t want it coming down more than .02 points a day. If you think it’s coming down faster than that then lower flow/gph through gfo

Gfo works like this...
If you have a lot of phosphate to remove use small amounts and change frequently.
Use larger amounts and remove less frequent if you use it for more stable phosphate.
Because larger amounts will slow down the flow, given you’re using the same pump/gph

What’s your nitrates?

Ok I finally got my act together to get my nitrates figured out. Nitrates are reading 0 ppm. Also tested phosphates again and they are reading 0.6ppm.

 

[HB Fisheye]

I wasn't real excited to see my nitrates were so low. This may be the reason some of my coral is losing color? Also why my cheato isn't growing so much?

 

[theMeat]

I wasn't real excited to see my nitrates were so low. This may be the reason some of my coral is losing color? Also why my cheato isn't growing so much?

Yup and yup.
Might want to feed more and keep running gfo. Or to do it faster dose nitrates and run gfo.

 

[dugthefish]

On a related note, how are you guys having high(er) PO4/NO3? I have to dose to keep a measurable amount or the dinos come back.