Carbon and GFO

[Jason0203]

I read somewhere that using GFO and Carbon can actually be bad for coral growth because the GFO lowers the PH and both take out nutrients the coral need.

I run GFO and my Phosphates are 0 but they are always low even when my GFO is old. It raises to around 0.25 but never higher and that is when I replace it. Do I need GFO at all or maybe not run it all the time?

I also put Carbon in a high flow area of my sump and just let it sit there for a month or so, but even when it is old I don’t get a spike in Ammonia. I feed my fish daily and my coral every 3 days. Should I be doing something different?

I’m asking because I am having a hard time lately keeping SPS coral alive and I can’t figure out why.

I have a 90 gallon DT and 30 gallon Sump
Ammonia: 0
Nitrate: 0
Nitrite: 0
Phosphate: 0
Calcium: 390 (I’m dosing CA to raise this)
ALK: 9 (Dosing ALK to maintain this)
Salinity 1.025
Temp: 79.2
PH: 7.9-8.0

Thanks for the help.

 

[LIreefguy]

Keeping sps are hard because they prefer very stable water conditions. It’s not just able numbers. It’s how stable you keep them day to day, week to week


By letting your Phosphates go from .25 to zero and back is causing the zooxanthella in the corals to go crazy in simple terms
Ideal levels will vary depending on who you ask
I try to keep my nitrates at 10 and Phosphates at .05

I test every week
I test alk ever 3 days
Alk imo is the most important one to test. Daily swings are likely to kill sps even when all other levels are fine

 

[Jason0203]

Keeping sps are hard because they prefer very stable water conditions. It’s not just able numbers. It’s how stable you keep them day to day, week to week


By letting your Phosphates go from .25 to zero and back is causing the zooxanthella in the corals to go crazy in simple terms
Ideal levels will vary depending on who you ask
I try to keep my nitrates at 10 and Phosphates at .05

I test every week
I test alk ever 3 days
Alk imo is the most important one to test. Daily swings are likely to kill sps even when all other levels are fine

I say my phosphates are .25 because that is the lowest reading my test kit gives. Also dumb question how do you keep your nitrates up? Mine are always 0.

 

[Rick.45cal]

It’s hard to keep corals with 0 NO3 and 0 PO4. It’s easier to keep corals if you have some of both. I’d lay off the GFO let some phosphates build up, then consider adding some nitrates by dosing (if none are detectable at that point). If you add nitrates with your water stripped of phosphates you’ll just make it harder on the corals you have left, possibly crashing your tank. Or you could always dose some phosphates too Just my $.02!

 

[LIreefguy]

I say my phosphates are .25 because that is the lowest reading my test kit gives. Also dumb question how do you keep your nitrates up? Mine are always 0.

.25 in Phosphates are high. Not low. What test kit are you using
You might want to switch to a long range test kit

 

[Jason0203]

.25 in Phosphates are high. Not low. What test kit are you using
You might want to switch to a long range test kit

I’m using the API Reef Master Kit. I figured that might be the problem so I bought a Hanna tester this afternoon.

 

[Jason0203]

Just tested with the Hanna Checker. Says I am at 0.187ppm.

 

[LIreefguy]

Just tested with the Hanna Checker. Says I am at 0.187ppm.

Still on higher end.
But Gfo but do you have Macro algae in your sump or refugium

 

[Jason0203]

Still on higher end.
But Gfo but do you have Macro algae in your sump or refugium

I have a little but they never seem to take hold and grow.

 

[MabuyaQ]

I have a little but they never seem to take hold and grow.

That is because you have no/to little nitrate available for algae to grow. One of the reasons you may struggle with SPS as well as their Zoöxanthellae also need nitrate. I would start dosing nitrate and keep using GFO to lower PO4 slowly and test for this regularly so you can keep it at around 0.05ppm.

 

[Jason0203]

That is because you have no/to little nitrate available for algae to grow. One of the reasons you may struggle with SPS as well as their Zoöxanthellae also need nitrate. I would start dosing nitrate and keep using GFO to lower PO4 slowly and test for this regularly so you can keep it at around 0.05ppm.

Any recommendations for what to use to dose Nitrate?

 

[Jason0203]

So I reduced the phosphate down to about .05ppm and started dosing Nitrate this afternoon. I have only dosed enough to raise my levels to 0.5ppm and I can already tell a difference is my corals overall happiness. Thank you for all your helpful tips. I will keep you updated as I try to get my nitrates to between 3-5ppm over the next week or two.

 

[MabuyaQ]

SPS have evolved in an environment with extremely stable water parameters. If you succeed in providing that in your aquarium they will reward you with great colors an growth. Growth to the point where certain species become 'weeds'.

 

[Jason0203]

SPS have evolved in an environment with extremely stable water parameters. If you succeed in providing that in your aquarium they will reward you with great colors an growth. Growth to the point where certain species become 'weeds'.

I already have “weeds,” I have a Kenya tree and a Pulsing Xenia that a friend gave me. I’m sure because he had, had enough of them. They’re small right now and look cool, but I am sure that will fade when they start to spread. Lol.

 

[135zman]

What did you end up using for Nitrate dosing?

 

[Jason0203]

What did you end up using for Nitrate dosing?

I bought some food grade potassium nitrate and mixed it with RODI water. Teaspoon mixed with 2000ml of water will give about 0.5ppm in a 100ml dose.

 

[nematode]

If you add nitrates with your water stripped of phosphates you’ll just make it harder on the corals you have left, possibly crashing your tank.

I was at 0 PO4 and 0 NO3 and started dosing nitrates and have had a relatively bad response with stn like symptoms appearing on several corals including acroporas and chalices .
Where does this opinion/idea/fact that adding nitrates with 0 PO4 "making it harder on the corals" come from. I'm not disagreeing, but would like to get more insight about this. Could you provide me with some links (threads, articles, ...) that discuss this issue.
I would appreciate it.

 

[Rick.45cal]

I was at 0 PO4 and 0 NO3 and started dosing nitrates and have had a relatively bad response with stn like symptoms appearing on several corals including acroporas and chalices .
Where does this opinion/idea/fact that adding nitrates with 0 PO4 "making it harder on the corals" come from. I'm not disagreeing, but would like to get more insight about this. Could you provide me with some links (threads, articles, ...) that discuss this issue.
I would appreciate it.

I’ve got personal experience from my current system, 2 seperate phosphate stavation events in the presence of ample nitrates with identical symptoms to what you describe. I’ve also read a handful of scientific studies available online. I can’t find the one that talks about increased mortality at this moment but here is another one that discusses phosphate limitation with elevated nitrates, versus elevated nitrates and elevated phosphates, versus low nitrate with low phosphates. Spoiler alert the HN/LP (high nitrate/low phosphate) conditions are the worst of the bunch for the test corals. It’s an interesting read
Page 8, “section 4.1 Effect of High Nitrate/ Low Phosphate conditions” is where it talks directly about this situation. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5441187/

 

[Randy Holmes-Farley Verified Community Expert]

I was at 0 PO4 and 0 NO3 and started dosing nitrates and have had a relatively bad response with stn like symptoms appearing on several corals including acroporas and chalices .
Where does this opinion/idea/fact that adding nitrates with 0 PO4 "making it harder on the corals" come from. I'm not disagreeing, but would like to get more insight about this. Could you provide me with some links (threads, articles, ...) that discuss this issue.
I would appreciate it.

I don’t have any articles to list on this, but it seems fairly likely to be true. The added nitrate is being used by something that also necessarily uses some phosphate to grow.

If phosphate is already in short supply, you may be making it even harder to come by, and hence may stress organisms that need it.

 

[Saltyreef]

Most of my coral lost color @ 0 nutrients until i turned off my skimmer and started feeding heavier. Zoas, lps and sps all lost color.