Nitrates stuck at 25 ppm

[Ordovician_Reef]

So I have my fuge on a 22 hour photo cycle and export algae bi-weekly, I change filter socks every other day and 10% weekly water changes, but my Nitrates are always 25 ppm. Now I am not overly concerned but I am adding a lot of SPS and want to hear peoples thoughts on that level. I guess my panic level would be 30-50 ppm.

Most of my corals are doing well, Porites, Stylophora, Stylocoeniella and Montipora are thriving. Psammocora and Leptoseris shocked when I moved them in but are recovering.

Phos 0.1
Alk 8.6
pH 8.26 - 8.45 daily range
calc 450
mag 1340

 

[jda]

Are you sure about the test?

With SPS, there are many that won't care at all about 25 ppm of no3, but some that will not live, slowly melt away and die. Not all of them can handle this, but plenty that can. As your no3 gets higher, the subset of SPS that are cool with higher no3 lowers. It looks like you have a subset of these already. You can find acropora to match if you like.

You can either lower it or just pick acropora that do not care. There are some very colorful and nice SPS that don't seem to mind no3 at 100. I would not want the no3 to get much above 25.

 

[Ordovician_Reef]

Are you sure about the test?

With SPS, there are many that won't care at all about 25 ppm of no3, but some that will not live, slowly melt away and die. Not all of them can handle this, but plenty that can. As your no3 gets higher, the subset of SPS that are cool with higher no3 lowers. It looks like you have a subset of these already. You can find acropora to match if you like.

You can either lower it or just pick acropora that do not care. There are some very colorful and nice SPS that don't seem to mind no3 at 100. I would not want the no3 to get much above 25.

I am sure about the test, and I likely do over feed in order to preserve all of the filter feeders that came on the rock. I am trying to back off of the feeding a little and skim a little more aggressively. Most of these corals came from sources who I have heard say their Nitrates are near or even above 25.

 

[blecki]

What's your phosphate?

The first thing I would do to lower the nitrate is make sure phosphate is detectable - if it's zero, it means your refugium is removing as much nitrate as it can with your current inputs. Then I would stop harvesting it so much.

Or start a zoa garden. They love nitrate.

 

[Ordovician_Reef]

What's your phosphate?

The first thing I would do to lower the nitrate is make sure phosphate is detectable - if it's zero, it means your refugium is removing as much nitrate as it can with your current inputs. Then I would stop harvesting it so much.

Or start a zoa garden. They love nitrate.

The phosphates are steady around 0.1. I am adding a bunch more Zoanthids.

 

[jda]

Don't back off. The ammonia and many forms of phosphorous from the fish waste is what is getting usable building blocks to your corals. Up the export.

How old is your tank? Do you have a sandbed? Tanks from 6-12 months with a few inches of undisturbed sand can start to develop zones where there is no oxygen and the bacteria that live there convert no3 into N gas. This is the last step in the actual nitrogen cycle - like the scientific one that is cyclical and ongoing.

Getting the chaeto to grow, skimming more also can help with export.

 

[blecki]

Don't back off. The ammonia and many forms of phosphorous from the fish waste is what is getting usable building blocks to your corals. Up the export.

I don't disagree. Except that removing too much algae too frequently can limit it's ability to export. I'm suggesting to let it grow more before removing it, so that the refugium is fuller and is able to process more.

Removing algae does nothing for nitrate still in the water column... there's no reason to rush to remove it once it's bound stuff up either. Let it ride. More algae = more algae to grow = more nitrate consumed faster.

 

[PeterEde]

So I have my fuge on a 22 hour photo cycle and export algae bi-weekly, I change filter socks every other day and 10% weekly water changes, but my Nitrates are always 25 ppm. Now I am not overly concerned but I am adding a lot of SPS and want to hear peoples thoughts on that level. I guess my panic level would be 30-50 ppm.

Most of my corals are doing well, Porites, Stylophora, Stylocoeniella and Montipora are thriving. Psammocora and Leptoseris shocked when I moved them in but are recovering.

Phos 0.1
Alk 8.6
pH 8.26 - 8.45 daily range
calc 450
mag 1340

If you research here you'll find a lot that say Nitrate is not a problem with SPS. Stability is key to SPS.
Having said that many say Nitrate should be no more than 10.
I guess only personal experience will answer that.
My Nitrates are 20ish and I have 3 or 4 SPS that are all growing and decent polyp extension at night.

 

[Ordovician_Reef]

I don't disagree. Except that removing too much algae too frequently can limit it's ability to export. I'm suggesting to let it grow more before removing it, so that the refugium is fuller and is able to process more.

Removing algae does nothing for nitrate still in the water column... there's no reason to rush to remove it once it's bound stuff up either. Let it ride. More algae = more algae to grow = more nitrate consumed faster.

Great point. I was thinking about lengthening the interval between harvest.