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JustinReef

Nitrate/Phosphate "problem"

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Hi all! I have a bit of a strange but "not a bad problem to have", problem. Most of my years in reefing have been with larger tanks that struggled to export nutrients despite having refugiums, skimmers, carbon dosing ect. This time, I have a Nuvo 10G AIO tank that seems to have incredibly low nutrients... no matter what I do (even changed test kits thinking they were inaccurate). Nitrates are always around 0-2. Phosphate always undetectable.  I don't have to clean the glass more than once a week. No algae in the tank, so it's not algae consuming nutrients. No skimmer, no refugium, basically just weekly 2G water changes. I thought maybe 2G each week was too much so I switched to 2G every two weeks but nothing changed. More on that later. The only filtration is about 5 lbs of LR and Marine Pure bio spheres filling the middle back chamber (I would guess about 8 balls). I run Chemi-pure nano if I have had my hands in the tank but that is not often. 

 

The tank is 90% sps which of course are all pale, looks like a old school zeo tank...not something I like. They grow and have some polyp extension but not much. They grow at roughly half the pace I would expect. The other 10% of coral are gorgonains, zoas, a duncan and green star polyps. All of these grow incredibly fast. So weird, not what I would expect at all. The GSP is like a weed and I figure this is using some nitrates. 

 

There are two fish which are fed daily with basically as many pellets as they want. I feed the corals with Oyster feast (probably why the softies are actually growing) every night or two. 

 

I used to do weekly water changes but figured it was too much and switched to every two weeks. Nothing changed. I then went on vacation and therefore did no water change for a month and... yeah, you guessed it, nitrates were still low. Maybe just over 2 on a salifert test. 

 

I am pretty disappointed with my sps color and growth but I also don't want to go crazy and dump a bunch of food in the tank which in turn will just create new issues. I am hesitant to add one more fish because the tank is small and the two fish I have get along very well. 

 

 

Any ideas? 

 

 

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That's interesting...

 

How stable is your tank? If you have a lot of SPS in a 10G I would imagine depletion of your trace elements would be pretty great.

 

 

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Just now, Justind823 said:

That's interesting...

 

How stable is your tank? If you have a lot of SPS in a 10G I would imagine depletion of your trace elements would be pretty great.

 

 

Not much of an issue. I have an Apex and DOS to keep Alk and Ca steady. I continue small water changes every few weeks to make sure trace elements are fine but I do not test for anything other than Nitrate, Phosphate, Alk and Ca. Generally I test Alk every few days and Nitrates once a week. 

 

The tank is not going through as much Alk or Ca as I would have expected but that would be due to the fairly slow growth. I think the only sps that has grown quite fast is a Red Dragon...which I also find odd since for me they have been slow growing in the past. 

 

Honestly, I find this aquarium to be the strangest I have ever had. It really makes no sense to me. 

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I’m not really a fan of the ultra low nutrient systems with the pastels. I appreciate what people can do with those tanks, but it isn’t for me.

 

I’m dosing phospahte as it drops to zero pretty fast and started causing issues with dinos. I feed pretty heavily, but was still having issues getting phosphate up. I don’t feed for nutrients, I feed for coral growth and because I enjoy it. I don’t feel that feeding to increase nutrients is a good solution. You don’t really have controll of what the nutrient levels are, you are just hoping phosphate comes up without sending nitrate too high. Dosing a known quantity of the desired chemicals is a more stable and more reliable method of increasing nutrients. My ideas may be different coming from planted aquariums, but keeping elevated levels in proper ratios keeps the zooxanthellae fed and the corals healthy.

 

If you decide to start dosing phosphate, be aware that the phosphate will bind to the rocks and substrate initially, so it may take a while to get phosphate to start coming up (another reason feeding to raise nutrients is a poor recommendation). I think I ended up dosing something like 7-8 times the amount needed to bring my phosphate up to 0.03 before it started becoming even slightly detectable. Still take it slow and monitor, just be aware of that so you don’t think something is going wrong or that your kits are bad.

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1 hour ago, Beer said:

I’m not really a fan of the ultra low nutrient systems with the pastels. I appreciate what people can do with those tanks, but it isn’t for me.

 

I’m dosing phospahte as it drops to zero pretty fast and started causing issues with dinos. I feed pretty heavily, but was still having issues getting phosphate up. I don’t feed for nutrients, I feed for coral growth and because I enjoy it. I don’t feel that feeding to increase nutrients is a good solution. You don’t really have controll of what the nutrient levels are, you are just hoping phosphate comes up without sending nitrate too high. Dosing a known quantity of the desired chemicals is a more stable and more reliable method of increasing nutrients. My ideas may be different coming from planted aquariums, but keeping elevated levels in proper ratios keeps the zooxanthellae fed and the corals healthy.

 

If you decide to start dosing phosphate, be aware that the phosphate will bind to the rocks and substrate initially, so it may take a while to get phosphate to start coming up (another reason feeding to raise nutrients is a poor recommendation). I think I ended up dosing something like 7-8 times the amount needed to bring my phosphate up to 0.03 before it started becoming even slightly detectable. Still take it slow and monitor, just be aware of that so you don’t think something is going wrong or that your kits are bad.

Cool, thanks this is good advice. I agree about not feeding for the sake of raising nutrients. I know things could go south pretty fast. So I have been cautious about how much food goes into the tank. My fish are already quite chubby haha. 

 

I may try dosing phosphate. 

 

I am still really confused by why this tiny tank with minimal filtration is able to keep nitrate and phosphate so low. 

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Most people would pay serious money to have your problem (I suppose they do pay a lot trying to put themselves in your situation).

 

If you don’t have a lot of fish and corals in there, it could just be that your feeding just isn’t sufficient to bring nutrients up.

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I have a nuvo mixed tank, for a while I fed lightly and eventually nutrients bottomed out resulting in dinos. To combat them I dirtied up the tank and it took 3 weeks of increased feeding with no waterchanges to get po4 up. I didnt clean my glass at all and could barely see into the tank, but when I finally cleaned it the corals looked better than ever. No3 reached 40+ and po4 was 0.25. I've since realized my corals were starving. Now my goal is to continuing feeding more  and just do enough of a weekly WC to replenish trace elements and keep no3 below 20 and po4 below 0.1.

 

Point being dont fear a little excess nutrients. Feed more and your coarls should respond. 

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I never got the idea that the almost non detectable nutrients in the open waters around reefs meant that 0 phosphate and nearly non-detectable nitrate was ideal. Zooxanthellae are photosynthetic organisms that need the same macro nutrients land dwelling plants need. They also paradoxically state that the coral gets all the nutrients they need from the zooxanthellae, but do everything they can to starve out the zooxanthellae, depriving them of nutrients.

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Yes, there's studies showing that corals can take up po4 almost as fast as it's produced. This is just a assumption on my part, but I always assumed the near 0 levels were actually the result of so much biomass in the ocean that nutrients are consumed as quickly as they are produced. 

 

I mean there's tons of life and decay around reefs so I would think no3/po4 is constantly produced. Plus there's also always  plankton and algae  blooms and small/microfauna in the water so if anything wild corals have a constant source of food/nutrients. 

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The situation is not unique for established small nano tanks.  The ratio of biomass to water volume is typically quite high, hence the rapid depletion of nutrients..

 

For many years I was barely able to get a NO3 reading (~1 ppm) and undetectable PO4 (both Salifert kits) in a 12g with two adult Ocellaris Clownfish in it.  Corals had great color and good growth, so I just rolled with it and stopped testing these two parameters altogether.  Since you have pale SPS, I'd look at possibly adding another fish (primarily for increased ammonia production) assuming the two you have aren't large/very aggressive and/or reducing the water change volume.  I don't have any experience with adding phosphate directly, but if carefully managed it could be another good alternative.

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To get po4 detectable in order to fight dinos it took feeding nls pellets 2x a day, reef roids 1x a day, and rods food 1x a day along with zero chemical filtration and no waterchanges for 3 weeks. And my tanks young. 

 

 

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Im having a similar “issue”. 25 gallon lagoon, some marine pure balls, chemi pure blue, chaeto refugium and weekly 5g water changes. I have 6 fish, i feed fish heavily daily, feed corals 2x or more weekly and dose fuel 2x weekly. My n03 struggles to stay above 2ppm. Usually 1ppm. My po4 is around .01ppm. I don’t even bother changing up my nutrient export because my corals (zoas, lps, and sps) are colorful and thriving. I have actually started to experiment with how much food i can actually dump into my tank without raising my nutrient levels. Its pretty impressive 😅 i say if its not broke, don’t fix it. Your acros being pale and having slow growth can be due to other reasons beyond nutrient levels. I don’t think your tank is “too clean” even though your levels are borederline undetectable. Hobby test kits are only accurate to a certain extent and undetectable doesn’t necessarily mean not enough. I am of a belief that in a closed system, with ample feeding and bioload, its impossible to have true zero no3 or po4. 

 

What is your dkh and lighting? Low nutrients, high par and high dkh can definitely cause issues, especially to sps. With high dkh you want higher nutrients. With low nutrients, lower dkH. Par also plays a role in this

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Since we only measure PO4 (inorganic phosphate), it isn't unreasonable that people can have undetectable levels with hobbyist test kits.  To get the complete phosphate picture however, measuring organic phosphate is necessary (a Triton ICP test will do this).  Feeding a lot should provide the needed phosphate, regardless of what our hobby test kits say.

 

The OP's tank can be lacking in nutrients, but hard to tell without a pic and knowing what kind of fish/type of food fed/how often fed.

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All good points and feedback! 

 

Ill take some pics when the lights are on next.

 

Its 10g Nuvo (more like 7g of water) and there is a PJ Cardinal and a Randall goby/pistol shrimp pair. 

 

Light is a AI Prime about 7” off the water. Corals are half way up the tank or lower. 

 

DKH is generally 8 but was a bit low last time I checked, at 7.3 

 

Alk stays quite steady in this tank and I check it many times a week.

 

pics soon!

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On 3/15/2019 at 6:39 PM, Beer said:

I’m not really a fan of the ultra low nutrient systems with the pastels. I appreciate what people can do with those tanks, but it isn’t for me.

 

I’m dosing phospahte as it drops to zero pretty fast and started causing issues with dinos. I feed pretty heavily, but was still having issues getting phosphate up. I don’t feed for nutrients, I feed for coral growth and because I enjoy it. I don’t feel that feeding to increase nutrients is a good solution. You don’t really have controll of what the nutrient levels are, you are just hoping phosphate comes up without sending nitrate too high. Dosing a known quantity of the desired chemicals is a more stable and more reliable method of increasing nutrients. My ideas may be different coming from planted aquariums, but keeping elevated levels in proper ratios keeps the zooxanthellae fed and the corals healthy.

 

If you decide to start dosing phosphate, be aware that the phosphate will bind to the rocks and substrate initially, so it may take a while to get phosphate to start coming up (another reason feeding to raise nutrients is a poor recommendation). I think I ended up dosing something like 7-8 times the amount needed to bring my phosphate up to 0.03 before it started becoming even slightly detectable. Still take it slow and monitor, just be aware of that so you don’t think something is going wrong or that your kits are bad.

What do you does for phos? Sorry if you mentioned it and I missed it.

 

I as well am having issues with dino's and my phos is 0, nitrates 2.

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What I am dosing is slightly less than ideal as it is left over chemicals from my planted tanks that I broke down a while back. It has potassium and phosphate, so I need to monitor both, but it has been keeping my porassium about where I want it.

 

People will typically use trisodium phosphate. You want something with fairly high purity. It is usually easier to make a stock solution with a known concentration so you don’t have to calculate and measure out the dose every time. So much easier to be able to dose 1ml per 1ppm for your given tank volume.

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