Nitrates in Predatory Tank

[Lil Puff]

I have a 120 gallon tank that is not coming down from high nitrates. The stock list is a lunar wrasse, long spine pufferfish, dog face pufferfish, zebra eel, miniatus grouper. In the sump I have a algae reactor, a aqua one g220 protein skimmer and bio balls. the nitrates look like they are or above 120 ppm. I have started dosing with vodka 3 days ago and doing water changes with no change on the nitrates. I think I may need to upgrade my skimmer but can not do that with out upgrading my tank as a bigger skimmer will not fit in the sump. Are there any other ways of lowering the nitrates with out upgrading the skimmer?

 

[lion king]

Whats up with your algae reactor, running macro is one of the best ways to manage nitrates. What kind of algae are you using and hows your harvest. Vodka dosing takes a whie to show any results.

 

[HB AL]

I have a huge bioload and nopox is what I do, it helps keep my nitrates under 10. I have a skimmer and lots of rock and thats it.

 

[Lil Puff]

Whats up with your algae reactor, running macro is one of the best ways to manage nitrates. What kind of algae are you using and hows your harvest. Vodka dosing takes a whie to show any results.

I have got chaeto in te algae reactor but it hasn't grown since i got it one month ago. It is also covered in slime and other algae. I have been running the lights on a 16 hour cycle in the reactor but changed it to 10 hours today.

 

[Lil Puff]

I have a huge bioload and nopox is what I do, it helps keep my nitrates under 10. I have a skimmer and lots of rock and thats it.

Do you use a skimmer that is rated for a larger tank than what you have?

 

[HB AL]

Do you use a skimmer that is rated for a larger tank than what you have?

No, I'm using the vertex 180 that I used on my 90g, that I replaced with this 180g.

 

[lion king]

Sounds like you are playing catch up, so whatever you use it will take time. Macro algae works great but you will have to get the nitrates down to be at a level that is manageable. Vodka dosing also works but also doesn't work overnight. I've used nopox which is similar to vodka dosing, but now I use macro. I prefer macro and use a mix of caulerpa, gracalaria, and ulva. Caulerpa does outperform chaeto, but chaeto does work. I would continue doing water changes while doing what you are doing, and give it time.

 

[MaxTremors]

What are your phosphates? IME, if you are phosphate limited it’s nearly impossible to lower nitrates, macro algae won’t grow and carbon dosing won’t work. In my current tank i had high nitrates and undetectable phosphates for a hood six months, nothing worked to get them down (carbon dosing and chaeto). I then started dosing phosphates and within a month they went from 50ppm or so down to less than 10ppm. I’ve since started lowering the dose of vinegar and will be relying on just the refugium and skimmer.

One other thing that might be part of the issue is if you used only live rock and didn’t seed it with any real live rock. Since it’s FOWLR, I’m assuming you haven’t added any corals either. What I’m getting at is that bottled bacteria is fine for nitrification, but IME denitrification (or completing the nitrogen cycle) can take a very, very long time without a diverse biome, adding some live rock will give you some bacterial diversity which can help facilitate denitrification (happens deep within live rock and oxygen poor areas, the bacteria is anaerobic).

 

[Lil Puff]

Sounds like you are playing catch up, so whatever you use it will take time. Macro algae works great but you will have to get the nitrates down to be at a level that is manageable. Vodka dosing also works but also doesn't work overnight. I've used nopox which is similar to vodka dosing, but now I use macro. I prefer macro and use a mix of caulerpa, gracalaria, and ulva. Caulerpa does outperform chaeto, but chaeto does work. I would continue doing water changes while doing what you are doing, and give it time.

Is there any way to speed up the process?

 

[HB AL]

Ya, change 100% of the water but the corals won't like that.

 

[Lil Puff]

What are your phosphates? IME, if you are phosphate limited it’s nearly impossible to lower nitrates, macro algae won’t grow and carbon dosing won’t work. In my current tank i had high nitrates and undetectable phosphates for a hood six months, nothing worked to get them down (carbon dosing and chaeto). I then started dosing phosphates and within a month they went from 50ppm or so down to less than 10ppm. I’ve since started lowering the dose of vinegar and will be relying on just the refugium and skimmer.

One other thing that might be part of the issue is if you used only live rock and didn’t seed it with any real live rock. Since it’s FOWLR, I’m assuming you haven’t added any corals either. What I’m getting at is that bottled bacteria is fine for nitrification, but IME denitrification (or completing the nitrogen cycle) can take a very, very long time without a diverse biome, adding some live rock will give you some bacterial diversity which can help facilitate denitrification (happens deep within live rock and oxygen poor areas, the bacteria is anaerobic).

If there is hair algae growing in the dt does that mean there are phosphates in the tank as the hair algae is growing or could the hair algae be out performing the chaeto for the phosphates and consuming all of them? Would dosing phosphates make algae in the dt grow more? Would it be worth buying a phosphate test kit online to test if im low or just go straight to dosing phosphates?

 

[Lil Puff]

Ya, change 100% of the water but the corals won't like that.

I dont have any corals yet. Would changing all the water restart the nitrate cycle?

 

[MaxTremors]

If there is hair algae growing in the dt does that mean there are phosphates in the tank as the hair algae is growing or could the hair algae be out performing the chaeto for the phosphates and consuming all of them? Would dosing phosphates make algae in the dt grow more? Would it be worth buying a phosphate test kit online to test if im low or just go straight to dosing phosphates?

You definitely need a phosphate test kit if you want to figure out the nitrate problem. You need one that has high resolution (meaning that it can differentiate low ppm). I would recommend either the Hanna ULR phosphate checker, the RedSea Pro, or the Tropic Marin Pro (The Tropic Marin is the least expensive, it’s around $25). Until you know what your phosphates are it’s hard to recommend a course of action. I also wouldn’t recommend dosing vodka without being able to test phosphates. Also, what nitrate test kit are you using? If it’s API, I would also replace that (API test kits are notoriously inaccurate).

 

[Lil Puff]

You definitely need a phosphate test kit if you want to figure out the nitrate problem. You need one that has high resolution (meaning that it can differentiate low ppm). I would recommend either the Hanna ULR phosphate checker, the RedSea Pro, or the Tropic Marin Pro (The Tropic Marin is the least expensive, it’s around $25). Until you know what your phosphates are it’s hard to recommend a course of action. I also wouldn’t recommend dosing vodka without being able to test phosphates. Also, what nitrate test kit are you using? If it’s API, I would also replace that (API test kits are notoriously inaccurate).

Ok, I will purchase a phosphate test kit and phosphate up just in case. And you are correct I am using a API test kit i will purchase a different brand when i purchase the phosphate stuff. Why is dosing vodka with out knowing your phosphate levels bad?

 

[Goodair]

You need nitrates and phosphates for carbon (vodka) dosing to work. With the food your likely feeding, you prob do. You should also try not to shoot for quick level swings as that will cause more problems than you're solving in the long term.
-Have you noticed your skimmer pulling more crap out after the dosing, it should be.
-what and how often do u feed
-is algae reactor growing algae too slow or not at all? That slime on the chaeto is prob gha and you should wash it off in a fresh water,
- when you say 120 nitrates, is the number rising, did you test at a store to confirm the number is right,
- do you have food leftover on the floor/in crevices after feeding,
- how old is the tank, algae growing on rocks and glass should be exploding in growth if you got those nutrient levels,
-
As lionking mentioned, it may be catchup and the dosing just need time to drop the levels. Ideally the levels should drop and be manageable with just macro once everything balances out. Personally I have low nitrates just from macro and other photosynthetic animals, but phosphates are the ones that are high, assuming it's due to the food I feed.

 

[Lil Puff]

You need nitrates and phosphates for carbon (vodka) dosing to work. With the food your likely feeding, you prob do.
-Have you noticed your skimmer pulling more crap out after the dosing, it should be.
-what and how often do u feed
-is algae reactor growing algae too slow or not at all? That slime on the chaeto is prob gha and you should wash it off in a fresh water,
- when you say 120 nitrates, is the number rising, did you test at a store to confirm the number is right,
- do you have food leftover on the floor/in crevices after feeding,
- how old is the tank, algae growing on rocks and glass should be exploding in growth if you got those nutrient levels,
-
As lionking mentioned, it may be catchup and the dosing just need time to drop the levels. Ideally the levels should drop and be manageable with just macro once everything balances out. Personally I have low nitrates just from macro and other photosynthetic animals, but phosphates are the ones that are high, assuming it's due to the food I feed.

-The skimmer hasnt been taking out more crap and doesn't even fill up in 2 days
-I feed frozen prawns and i feed them every day or every second day depending on when they are hungry
-It is not growing at all
-The max reading the test can give is 120 ppm but the colour looks darker than the result given so it is likely more than 120 ppm. I live in outback australia and there are no stores to test my water at. I have ordered everything including my fish online.
-There are some little bits of prawn left over but no large chunks
-The tank is around 8 months old and there is a bit of algae but nothing extreme. I am going to be buying a better test kit online as MaxTremors suggested. Could the test kit be giving me false results?
Attatched below is an image of th algae
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[Goodair]

As for your rocks, that's pretty much bare clean. Can you take a picture of your skimmer, to see where the water breaks, it might need adjusting. Test kits, maybe, we could give better feedback once the other ones come in for sure. Macro is weird, some people just cant grow some kinds and it's a mystery why. Maybe you need to try calupra instead of chaeto. Have you tested your water change batch too?

 

[Lil Puff]

As for your rocks, that's pretty much bare clean. Can you take a picture of your skimmer, to see where the water breaks, it might need adjusting. Test kits, maybe, we could give better feedback once the other ones come in for sure. Macro is weird, some people just cant grow some kinds and it's a mystery why. Maybe you need to try calupra instead of chaeto. Have you tested your water change batch too?

I have not even tried testing my source water for nitrates thats a really good idea! I will test it with my current test kit and my new one when i get it. This is the best photo of my skimmer i can get as my sump has really tall walls.
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[Goodair]

Another picture of the neck, where the bubbling starts to happen. The valve on the skimmer will drop or raise that, but your skimate looks clear. If it gets darker/fills faster after some time while vodka dosing, then you will know it's working as that means more organics are being pulled from your water. So definitely keep on eye on that over the week.

 

[Lil Puff]

Another picture of the neck, where the bubbling starts to happen. The valve on the skimmer will drop or raise that, but your skimate looks clear. If it gets darker/fills faster after some time while vodka dosing, then you will know it's working as that means more organics are being pulled from your water. So definitely keep on eye on that over the week.

This is as good of a photo i can get and i will keep a close eye on how much organics it is taking out
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