Nitrates and Phosphates under control?

[brdk]

Hello everyone -

I am wondering about my nitrates and phosphates. My tank is 18 months old - an IM15 cube. I had a large GHA outbreak that got out of control. In the middle of February I did a massive manual removal, followed by an addition of two turbo snails. Every week I have slowly removed more GHA, and the snails removed the bits I could not remove from the rock. This week I finally feel that I have irradiated the GHA, and I have noticed that my corals have never looked better.

The thing that concerns me is my Nitrates and Phosphates. When I was dealing with my GHA outbreak, and even before the outbreak, my testing levels were within the parameters that are recommended by BRS. Now that I have my GHA under control, I am watching my nitrates and phosphates rise. I assume the GHA was feeding off the nitrates and phosphates which kept them "in check".

This brings me to my main question - as I am conflicted. Should I be doing anything to bring these levels down now that the GHA is gone? Reactor with GFO? Bigger water changes? Less feeding? Looking at the numbers, my levels are high. Looking at the corals, I am super happy. At what point do I start to worry about nitrates and phosphates getting too high?

My next thought is to add a birdsnest frag and try my hand at SPS, but want my tank to be ready for that type of coral as well.

I have attached a picture of my weekly testing log as well as the corals which I am very happy with!

I hope somebody can chime in who has dealt with this situation before.

Thanks!

 

[Eric Cohen Verified Sponsor]

Hi brdk!

Eric from Tank Stop here. First off, congrats on successfully battling that GHA outbreak! It can be quite persistent, so your manual removal approach combined with those turbo snails clearly did the trick.

What you're experiencing with rising nitrates and phosphates after GHA reduction is actually very common. You're absolutely right that the algae was consuming those nutrients, and now that it's gone, they're becoming more measurable in your water column.

For a 15-gallon IM cube, here's what I'd recommend:

1. Start with feeding adjustments first - This is always the easiest and most natural approach. Try reducing feeding slightly or switching to foods that produce less waste. Many hobbyists overfeed without realizing it.
2. Moderate water changes - Rather than massive water changes that can shock your system, consider doing more frequent smaller changes (10-15% twice a week instead of one larger change).
3. GFO as a last resort - While GFO works well, it can sometimes be too aggressive for smaller systems. If you do go this route, use a very small amount at first and monitor your levels closely. Rapid phosphate drops can stress corals.

The good news is that your corals are looking happy despite the elevated nutrients, which tells me you're in a manageable range. Many SPS actually prefer slightly higher nitrates (5-10ppm) than what was traditionally recommended years ago.

For your birdsnest addition, I'd recommend stabilizing your parameters for at least 2-3 weeks before introducing it. Birdsnests can be more forgiving than other SPS, but consistency is key.

If you're looking to move more into SPS, feel free to check out our selection at TankStop.com. We quarantine all our SPS for at least two weeks before shipping to ensure they're healthy and pest-free. We just got some spectacular birdsnest colonies in this week that would be perfect for your setup.

Happy Reefing! Eric

 

[Randy Holmes-Farley Verified Community Expert]

The nitrate and phosphate are within my target range:
https://www.reef2reef.com/ams/randy’s-thoughts-on-nutrient-target-ranges.1087/

4. What targets seem reasonable? Of course, that depends on all the other factors at play, such as types of corals, availability of ammonia, particulate foods, etc. However, for a mature mixed reef, this would be how I personally would run it:

• Let nitrate float between 5 ppm and 50 ppm. I’d use gentle export in this range, such as growing macroalgae.
• Above 50 ppm, I’d begin to focus more on reducing it, by organic carbon dosing, turf or macroalgae, etc.
• Below 5 ppm, I’d begin to dose ammonia or feed more. The target level might drop lower if dosing ammonia, just like the heavy in/heavy out scenario where nitrate may not be as needed.
• Let phosphate float between about 0.06 ppm and 0.3 ppm. This range is higher than I’ve recommended in the past. I’d use gentle export in this range, such as growing macroalgae.
• Above about 0.3 ppm, I’d begin to focus more on reducing it, by turf or macroalgae, or a binder such as GFO or lanthanum (has its own risks to tangs). If a binder: GO SLOW. Turf and macroalgae will typically be slow enough.
• Below 0.06 ppm, I’d begin to dose sodium phosphate or feed more to get the level up.

 

[CHSUB]

Many SPS actually prefer slightly higher nitrates (5-10ppm) than what was traditionally recommended years ago

While I agree with your reply overall, here is a discussion point. How would anyone actual know that SPS’s prefer higher no3? I don’t believe they do, only that they can tolerate higher levels. Hobbyists observe corals not being affected by high levels and appear to continue growing and “color up”; when it reality something else caused the improvement beyond hobbyist’s ability to understand and than automatically assume increased no3 is the reason.

 

[brdk]

Thank you for the replies. At this point, I am going to try feeding less, and I will throw in an additional 10% water change mid week. Hopefully I see an improvement in a couple weeks.

 

[Lavey29]

You want 10 to 20 nitrates and. .1 to .2 phosphate for those corals.

 

[BryanM]

Hello everyone -

I am wondering about my nitrates and phosphates. My tank is 18 months old - an IM15 cube. I had a large GHA outbreak that got out of control. In the middle of February I did a massive manual removal, followed by an addition of two turbo snails. Every week I have slowly removed more GHA, and the snails removed the bits I could not remove from the rock. This week I finally feel that I have irradiated the GHA, and I have noticed that my corals have never looked better.

The thing that concerns me is my Nitrates and Phosphates. When I was dealing with my GHA outbreak, and even before the outbreak, my testing levels were within the parameters that are recommended by BRS. Now that I have my GHA under control, I am watching my nitrates and phosphates rise. I assume the GHA was feeding off the nitrates and phosphates which kept them "in check".

This brings me to my main question - as I am conflicted. Should I be doing anything to bring these levels down now that the GHA is gone? Reactor with GFO? Bigger water changes? Less feeding? Looking at the numbers, my levels are high. Looking at the corals, I am super happy. At what point do I start to worry about nitrates and phosphates getting too high?

My next thought is to add a birdsnest frag and try my hand at SPS, but want my tank to be ready for that type of coral as well.

I have attached a picture of my weekly testing log as well as the corals which I am very happy with!

I hope somebody can chime in who has dealt with this situation before.

Thanks!

Primarily I fit in to the camp of: Don't bottom either out and let your tank be your guide.

You can search for days and come up with ultra low nutrient systems that thrive, and the reverse, extremely dirty water systems that equally thrive.

I think I'd start "caring" about nitrates past 50, and phosphates above .3 or so.

 

[Eric Cohen Verified Sponsor]

While I agree with your reply overall, here is a discussion point. How would anyone actual know that SPS’s prefer higher no3? I don’t believe they do, only that they can tolerate higher levels. Hobbyists observe corals not being affected by high levels and appear to continue growing and “color up”; when it reality something else caused the improvement beyond hobbyist’s ability to understand and than automatically assume increased no3 is the reason.

Totally true and great talking point indeed! Is it the relation of Nitrates and Phosphate that plays a role? Redfield chart out the window? I think we have seen colors fade in sps when levels get too low but how low is too low and how high is too high I believe can vary from tank to tank. It’s more of a general range that we can aim for and now better control with more precise dosing and testing. Good point!

 

[exnisstech]

Your numbers look good to me and coral look good. If anything I would bring nitrate up a little.

 

[brdk]

Your numbers look good to me and coral look good. If anything I would bring nitrate up a little.

My phosphates test right in line with yours at the moment. The nitrates are a bit low. If I wanted to increase nitrates, how can I do that without increasing the phosphates at the same time? Wouldn't an increase in food increase both parameters?

 

[exnisstech]

It would and I apologize I was thinking out loud. I probably wouldn't do anything to intentionally raise nitrate at this point. You could lower PO4 using various methods but TBO I would probably watch them as well. I like to watch coral and use them to decide if any action is required. Your tank looks great.