Are Nitrate Tests really a good indicator of Nutrient Level?

[d2mini]

In some instances I would imagine, yes. For instance, if you're Nitrates are testing at 50 ppm, you have to have an excess of nutrients in the system.

But lets say you're running a really clean tank, but your filter socks are getting pretty dirty. I don't use them but folks say that this can cause Nitrates to rise.
Some folks say that if your Nitrates are too low, feed more.
Some folks say add more fish.
Some folks say dose a source of Nitrate like stump remover for example.

When looking at these various instances, are they all considered the same when it comes to the health of our coral and their nutritional needs?
Or do the nitrates from something like stump remover do nothing for feeding a coral or much less than adding more fish poop?
What about increased nitrate from coral specific foods?

I don't know if this makes any sense but this is what's floating around between my ears this morning.
I tend to be on the very low end when it comes to Nitrate testing. So when needing to up nutrient levels I'm curious what is the better approach, not only for offering an immediate food source for the coral but also for avoiding issues long term, like some kind of nutrient build up.

 

[Labridaedicted]

Nitrates are a decent indicator of nitrogen levels in the tank since the bacteria usually don't break it down further.

Nitrates alone don't make a high nutrient system. With high (within acceptable range, though) nitrates and very low phosphates, you would see very little of the adverse effects. That's why poop and food breaking down do more than adding a chemical. It's the complexity of the composition feeding all kinds of other trace elements to the system I addition to nitrogen.

This is just how I understand it, though.

The ideal way would be to test for all nitrogen and phosphorous sources to determine nutrient levels. However, phosphate and nitrates tend to be the most common compounds containing these elements in the system and thus serve as a relatively good indicator of total levels in a mature system.

 

[Randy Holmes-Farley Verified Community Expert]

Organisms that consume nitrate (or might possibly be negatively impacted by it) neither know nor "care" how the nitrate got into the water.

Nitrate should not be considered an indicator of the levels of any other nutrient (phosphate, ammonia, trace metals, etc.).

 

[dragon99]

Or do the nitrates from something like stump remover do nothing for feeding a coral or much less than adding more fish poop?

That seems like the million dollar question.

Nitrate should not be considered an indicator of the levels of any other nutrient (phosphate, ammonia, trace metals, etc.).

So are nitrates alone enough of a nutrient source for corals? Or are the other nutrients just as important?
My assumption is for folks that dose KNO3 and see improvement: they are limited by the NO3 specifically, but have other available nutrients.

 

[Randy Holmes-Farley Verified Community Expert]

So are nitrates alone enough of a nutrient source for corals? Or are the other nutrients just as important?
My assumption is for folks that dose KNO3 and see improvement: they are limited by the NO3 specifically, but have other available nutrients.

It may or may not be an adequate source of nitrogen (depending on the organism and how much is there), but it definitely is not sufficient for growth. Many other nutrients are absolutely required.

In many cases, a source of nitrogen is limiting to organisms, but certainly not all cases. Iron can be limiting, as can phosphate, and very likely other trace metals as well.

 

[d2mini]

In many cases, a source of nitrogen is limiting to organisms, but certainly not all cases. Iron can be limiting, as can phosphate, and very likely other trace metals as well.

This is part of what I was wondering.
N03 and P04 are two things we can test for, but just because one is low, doesn't mean that's ALL that is low.
So if one's tank is low in n03, dosing pure potassium nitrate would really not be an effective solution.
And I'm speaking specifically to coral health/nutritional needs.

 

[dragon99]

It may or may not be an adequate source of nitrogen (depending on the organism and how much is there), but it definitely is not sufficient for growth. Many other nutrients are absolutely required.

In many cases, a source of nitrogen is limiting to organisms, but certainly not all cases. Iron can be limiting, as can phosphate, and very likely other trace metals as well.

And now I need to re-read all your articles. You've posed more useful knowledge than I can ever remember.

 

[Randy Holmes-Farley Verified Community Expert]

This is part of what I was wondering.
N03 and P04 are two things we can test for, but just because one is low, doesn't mean that's ALL that is low.
So if one's tank is low in n03, dosing pure potassium nitrate would really not be an effective solution.
And I'm speaking specifically to coral health/nutritional needs.

Well, many folks have seen immediate benefits. It's not just a hypothesis.

If corals are deficient in other things too, then dosing them may also be useful. And many folks do. Some dose phosphate, some nitrate, some both, some dose iron, and many dose mixtures of many trace elements. It all depends on what you think your system will benefit from.

 

[Damien Buckley]

I'm no scientist nor expert but we seem to be stuck into the idea that we need low nitrate/phosphate levels to keep algae down, yet we see all the time really successful tanks with little or no nuisance algae with nitrates from 50-100ppm and people struggling with tanks overran with algae with nitrates under 10 & low phosphate. My last tank (long time ago) had high a deep sand bed, a worthless skimmer, high nitrate, no phosphate tests, and no nuisance algae at all. Go figure. I honestly think there's very little real understanding of most of the processes going on in our tanks and no really definitive proof.

 

[Paul B]

I'm no scientist nor expert but we seem to be stuck into the idea that we need low nitrate/phosphate levels to keep algae down,

I totally agree. Nitrate and Phosphate have nothing to do with high algae growth but that rumor will always persist. Algae blooms are usually high in a brand new tank with all new water and no nitrates. Why is that?
Old tanks with high nitrates and phosphates usually have no algae, interesting isn't it.

I took this off a practically uninhabited very remote Hawaiian Island in the middle of the Pacific Ocean where for some reason, the tangs disappeared. Looks like hair algae to me.
My tank has nitrate readings of 160 and my phosphate is 2.0. I have no algae at all, I wish I did.

 

[d2mini]

I'm no scientist nor expert but we seem to be stuck into the idea that we need low nitrate/phosphate levels to keep algae down, yet we see all the time really successful tanks with little or no nuisance algae with nitrates from 50-100ppm and people struggling with tanks overran with algae with nitrates under 10 & low phosphate.

I don't try for low nutrients. I struggle with low nutrients. If I don't actively try to get nutrients up, my n03 will test 0 ppm.
p04 on the other hand is usually between .06 and .1 for me.

 

[pelphrey]

I don't try for low nutrients. I struggle with low nutrients. If I don't actively try to get nutrients up, my n03 will test 0 ppm.
p04 on the other hand is usually between .06 and .1 for me.

I'm in a similar situation. Nitrates always test zero and phosphates .06-.09 Thats running my RAIN2 ATS 24/7 with just 2 of the 4 lights and skimmer. No socks in the sump, with a healthy amount of pond matrix.

 

[chefjpaul]

Im in a similar situation on this new tank as well.
We need to consider par levels as well, as I try to "dirty" up my tank, I had to lower my par as I found my corals loosing colors.

In my case currently, it's lack of PO4, cant test higher than zero, although I know its there.
I started this system totally clean, sterile and dry, so its a very different experience now not fighting browning corals to fighting pale / bleach trying to naturaly.

 

[d2mini]

I had to lower my par as I found my corals loosing colors.

I did this just this week.
Some of my sps were getting a little dull.
Trying to feed more coral specific food, too.