Nutrients

[One Eyed Bunny]

When we discuss nutrient rich water, I feel we do not all have an exact definition of what nutrient rich water is. Is high or low 500ppm or 3ppm? Do we go by TDS? Do we factor in ammonia, nitrites, and/or nitrates?

 

My concern with this is that I, myself, do not entirely understand what we mean when we discuss what nutrient rich or nutrient deficient water is. This comes into play when treating algae blooms, feeding corals, and the over all health of our tanks.

 

So, lets discuss, what do we mean why nutrient rich and nutrient deficient water in operational terms.

[jeremai]

My take:

 

When I think of 'nutrient-rich' waters, I think of nutrients in their inorganic forms. Organic waste gets broken down by various processes into its inorganic form (nitrates and phosphates, along with a few others).

 

Nutrient-rich water would have a ready supply of these 'building blocks', regardless of test results (my 29g tests zero for nitrates, but the constant algae smothering everything tells otherwise). Nutrient-deficient water would be basically inert - think high-tech SPS tanks. No nitrogenous compounds or phosphates.

 

TDS is different, and since I never came across the term in the field, I have no idea how it factors in here.

[Mr. Fosi]

Is high or low 500ppm or 3ppm? Do we go by TDS? Do we factor in ammonia, nitrites, and/or nitrates?

 

Depends on your system, but at all times, NH3, NO2, NO3 and PO4 should be included.

 

There are a lot of other things (compounds or elements) that could be considered "nutrients" (Example: iron) but we don't usually track them because there is only a very slim chance to build up a preponderance of them in our systems.

 

If you are running a stony system, "high nutrients" could be 0-5 mg/l of NO3 or 0-0.2 mg/l of phosphate. The difference in concentration ranges is due to differential usage of different elements.

 

A good way to think of nutrients is in ratios. One such ratio (developed in marine systems) is the redfield ratio: C:Si:N:P = 106:15:16:1

 

So, lets discuss, what do we mean why nutrient rich and nutrient deficient water in operational terms.

 

Nutrient deficiant water is generally a different matter. We will always have enough N in our tanks and if we use tap water, we will likely have more than enough PO4 as well.

 

This is why you usually don't hear about nutrient deficiancy in terms of N, P, or C. Generally, in marine aquaria, nutrient deficiancy usually means something like I, Zn, Mo, Me, Th or some other element that is used by our livestock but gleaned from the water (salt mix) or, in the case organisms, direct ingestion of food.

 

When I think of 'nutrient-rich' waters, I think of nutrients in their inorganic forms. Organic waste gets broken down by various processes into its inorganic form (nitrates and phosphates, along with a few others).

 

A good way to think of them, but PO4 isn't an organic compound.

 

Nutrient-rich water would have a ready supply of these 'building blocks', regardless of test results (my 29g tests zero for nitrates, but the constant algae smothering everything tells otherwise).

 

A great point. When we do water tests, we have to remember that we are only getting readings of what is left in the water after our tank inhabitants (corals & fish as well as bacteria & microalgae) have taken what they want.

 

If you are getting a reading on a test result (any test result), you can usually assume that you have more of whatever you tested than what your tank inhabitants need.

 

That is how we think of "nutrients" in limnology and oceanography.

[mybuickskill6979]

personally when i think of nutrient rich water i think of the bad stuff. nitrate and phosphate. in mraine systems it is how much is in there its that there is any in there. espceially with reefers.

i think of it in realtion to what we happen to be talking about in fresh water id say 20ppm of nitrate is alright. in a coral tank i'd say damn thats nutrient rich hehe.

 

im rambling a little so i'll stop now!!

[jeremai]

Like Fosi said, it depends on the system. seabass is adding nutrients to his contest tank because of the seagrass; I don't mind them because my corals can deal with it, but someone running a system filled to the brim with Acropora may feel differently.

 

In the ocean, nutrient-rich water is the only reason life exists. Organic wastes drift down to the deep ocean, where they are broken down. Upwellings bring the nutrients into contact with sunlight, and this sets the stage for phytoplankton blooms - and the rest of the chain grows from there.

 

Unless, of course, it is an El Nino year; then it's a whole different scenario...

[chuckfullservice]

Other then water changes do any of you add any type of nutrients to your tank?

I have been using a ph buffer because my ph is still hanging around 8.4 and I would like to keep it around 8.2 .

But after the addition of this buffer I have noticed a positive response from my live stock . Snail had babys , recent pod bloom also crabs molting I can only account this to the addition of carbonate .

 

Kent marine super buffer dkh

Maybe there is another factor here but it seems my live stock has responded positively to this .