Taking GFO offline

[Duncan Tse]

Everything seems to be doing fine for now but would there be a problem later down the road with low phosphates and high nitrates?

Currently only using 1 tbsp of gfo in a 37 gallon reef and that depletes about 0.01ppm PO4 a day. Worried that I would be getting 0 PO4 reading so I've been feeding more recently. Hovering around
0.03ppm PO4 right now.

The problem is that because I'm feeding more, nitrates are climbing up and its currently sitting at 25ppm.

Should I take the gfo reactor offline and just feed less to bring down nitrates?

Any input is appreciated

Thanks

 

[Quietman]

I would reduce the GFO slowly (not offline) or perhaps move to other less aggressive phosphate media (Phosguard for example).

No need to have high nitrates just for phosphates unless that's how you wish to manage the nutrients.

 

[Duncan Tse]

Tank is 2 years old and I've started adding acros about 3 months ago

 

[Quietman]

Also, you may wish to have a bit more aggressive nitrate removal...carbon dosing or fuge or ..(the list is long).

 

[Duncan Tse]

I would reduce the GFO slowly (not offline) or perhaps move to other less aggressive phosphate media (Phosguard for example).

No need to have high nitrates just for phosphates unless that's how you wish to manage the nutrients.

May try doing 0.5 tbsp next time I switch out gfo

Another question is would 25ppm nitrates affect corals in the long run? More worried about the acros but they seem to be holding onto their colors for the first 3 months

 

[Quietman]

Was thinking about a more complete answer...

You need to manage Phosphate and Nitrate independent of each other. You're unlikely to find one solution that does both to the parameters you wish to keep. This is because organisms take up nutrients at different rates and that will vary over tank life and different organisms compete for nutrients. That's one reason why weekly testing for first year until maturity is recommended. Hope that helps.

 

[Duncan Tse]

Also, you may wish to have a bit more aggressive nitrate removal...carbon dosing or fuge or ..(the list is long).

My current setup is very simple with just a protein skimmer, carbon, and gfo right now. Would carbon dosing work effectively as I have the reef Octopus HOB Skimmer and it does an okay job.

 

[Quietman]

May try doing 0.5 tbsp next time I switch out gfo

Another question is would 25ppm nitrates affect corals in the long run? More worried about the acros but they seem to be holding onto their colors for the first 3 months

Some manage very successful tanks at those levels long term. I would think most on here would consider that a bit high for sensitive corals though. But you can't argue with how they look...if it ain't broke, don't fix it. Or at least don't fix it too quickly....adjust your gfo, ease off the feeding, see where you end up. Closely monitor tank/corals for reactions.

 

[Duncan Tse]

Was thinking about a more complete answer...

You need to manage Phosphate and Nitrate independent of each other. You're unlikely to find one solution that does both to the parameters you wish to keep. This is because organisms take up nutrients at different rates and that will vary over tank life and different organisms compete for nutrients. That's one reason why weekly testing for first year until maturity is recommended. Hope that helps.

Okay I see where you're coming from. I ways thought that you can maintain ideal phosphate and nitrate parameters dependent of each other. Never thought about hitting both levels using different methods.

 

[Quietman]

My current setup is very simple with just a protein skimmer, carbon, and gfo right now. Would carbon dosing work effectively as I have the reef Octopus HOB Skimmer and it does an okay job.

Yup...I have skimmer only (some carbon occasionally) and use carbon dosing (NOPOx) for my nutrient removal. Sometimes my phosphates pop up a bit and I may add Phosguard or PhosphateRx (if I want a quick knock down).

 

[Duncan Tse]

Some manage very successful tanks at those levels long term. I would think most on here would consider that a bit high for sensitive corals though. But you can't argue with how they look...if it ain't broke, don't fix it. Or at least don't fix it too quickly....adjust your gfo, ease off the feeding, see where you end up. Closely monitor tank/corals for reactions.

Thanks for your feedback. One thing I've learned in this hobby is to go slow on everything you do. I think my plan now is to ease off of gfo and feed less. Test daily for now to see where my levels are at

 

[Duncan Tse]

Yup...I have skimmer only (some carbon occasionally) and use carbon dosing (NOPOx) for my nutrient removal. Sometimes my phosphates pop up a bit and I may add Phosguard or PhosphateRx (if I want a quick knock down).

Sounds like a solid plan. I think once the removal of gfo and less feedings and I'm still getting 25ppm nitrates. I may try to dose carbon slowly to knock down my nitrates.

 

[Devisissy]

Was thinking about a more complete answer...

You need to manage Phosphate and Nitrate independent of each other. You're unlikely to find one solution that does both to the parameters you wish to keep. This is because organisms take up nutrients at different rates and that will vary over tank life and different organisms compete for nutrients. That's one reason why weekly testing for first year until maturity is recommended. Hope that helps.

Maybe the removal of them but low phosphates usually push nitrates much higher.

 

[Quietman]

Maybe the removal of them but low phosphates usually push nitrates much higher.
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Usually? I've run low nitrates with steady low phosphates most of the time only periodically requiring any phosphate removal media. What's the mechanism for low nitrates causing high phosphates?