Nitrates and Phosphates...

[fredro]

Why can some people have a tank with a few fish and feed lightly, but battle high nitrates and phosphates, while others can have the same setup witha ton of fish and feed heavily, yet never get nitrates to register? Is there some kind of strain of super-bacteria that some tanks have which just eats up nitrates? Im in the second group and while its nice to not have to battle keeping down crazy nutrient levels, it sucks for the colors of my corals.

And on top of that, my PO4, although read 0.00 (hanna) must still be present, because my corals arent just pale, theyre browning too

 

[Nano sapiens]

The bacterium that we rely upon for nitrate and phosphate cycling require an adequate carbon source (food stuffs, dosed carbon, etc.). If the carbon source is inadequate, and/or the carbon can't properly get to the bacteria due to inadequate flow in the substrate (typically caused by heavy detritus buildup), denitrification and phosphate cycling will be incomplete leading to a buildup of these substances.

PO4 (inorganic phosphates) are only part of the phosphate family of species and if you have growing algae in the tank, you have PO4 that is being sequestered. If you feed heavily, you are providing a source of organic phosphate that the corals need for growth and pigmentation, but our hobbyist grade test kits can't measure it.

Browning corals can be caused by a number of other factors including lighting issues, swinging parameters, etc. May not be linked to nutrient levels directly.

 

[Randy Holmes-Farley Verified Community Expert]

Why can some people have a tank with a few fish and feed lightly, but battle high nitrates and phosphates, while others can have the same setup witha ton of fish and feed heavily, yet never get nitrates to register? Is there some kind of strain of super-bacteria that some tanks have which just eats up nitrates? Im in the second group and while its nice to not have to battle keeping down crazy nutrient levels, it sucks for the colors of my corals.

And on top of that, my PO4, although read 0.00 (hanna) must still be present, because my corals arent just pale, theyre browning too

There are many different ways that nutrients are removed from reef systems, include growing organisms of all sorts. Even without specific methods employed (like growing macroalgae), many people can keep them adequately low. I'm not entirely sure what the most important differences are, but with respect to nitrate, it may be the quality of the sand and rock permitting sufficient denitrification or not. With respect to phosphate, even the method of supplementing calcium and alkalinity may have an impact since some emthods may induce more precipitation of calcium carbonate, which may incorporate phosphate.

These have more:

Phosphate In The Reef Aquarium
https://www.reef2reef.com/blog/?p=3184

Nitrate in the Reef Aquarium - REEFEDITION
https://www.reef2reef.com/blog/nitrate-in-the-reef-aquarium

 

[fredro]

There are many different ways that nutrients are removed from reef systems, include growing organisms of all sorts. Even without specific methods employed (like growing macroalgae), many people can keep them adequately low. I'm not entirely sure what the most important differences are, but with respect to nitrate, it may be the quality of the sand and rock permitting sufficient denitrification or not. With respect to phosphate, even the method of supplementing calcium and alkalinity may have an impact since some emthods may induce more precipitation of calcium carbonate, which may incorporate phosphate.

These have more:

Phosphate In The Reef Aquarium
https://www.reef2reef.com/blog/?p=3184

Nitrate in the Reef Aquarium - REEFEDITION
https://www.reef2reef.com/blog/nitrate-in-the-reef-aquarium

That makes sense. But do I have excess phosphates in my water or no? The tests all say 0.00ppm, but I have some browned SPS and have some spots of bubble algae that keep growing. I run a ZEOvit carbon dosed system and have no macros in my sump, just a skimmer and ZEO reactor. People say po4 can test 0.00ppm when the other Algae in the system is using it up faster than it can be tested for, but I'm guessing that's not possible without a refugium or a tank FULL of algae, neither of which I have.

 

[Randy Holmes-Farley Verified Community Expert]

Well, excess is a relative term.

Yes, algae obviously can take up nutrients fast even at low levels (like when using a large ATS) so the phosphate is fluxing through the system from food to algae, even if the levels read low, and intercepting it (like with GFO or bacteria) before the algae gets it can often succeed, depending on the type of algae.

However, bubble algae (valonia) is very hard to get rid of by reducing nutrients since it may take levels lower than other organisms would like. So I'm not sure I'd try to tackle it this way.

As to the "brown" corals, that can be hard to diagnose. Were they more colorful in this same tank in the past?

 

[fredro]

No. They have always been paled and some browned, before and after zeovit. Before ZEOvit, I had a fuge that would grow a plastic shopping bag of Chaeto every 3 weeks. I'm leaning toward my shallow sandbed. I have. 1" fine sandbed that started as CaribSea AragAlive, which I'm considering removing and swapping out for a coarse aragonite crushed coral substrate, as recommended to use with ZEOvit

 

[Randy Holmes-Farley Verified Community Expert]

No. They have always been paled and some browned, before and after zeovit. Before ZEOvit, I had a fuge that would grow a plastic shopping bag of Chaeto every 3 weeks. I'm leaning toward my shallow sandbed. I have. 1" fine sandbed that started as CaribSea AragAlive, which I'm considering removing and swapping out for a coarse aragonite crushed coral substrate, as recommended to use with ZEOvit

Maybe the brownish is lighting, not nutrients.

 

[fredro]

Maybe the brownish is lighting, not nutrients.

Lack of?

I assumed an ATi 8x54w over a 16" deep tank would be more than sufficient

 

[Randy Holmes-Farley Verified Community Expert]

Lack of?

I assumed an ATi 8x54w over a 16" deep tank would be more than sufficient

Color and lighting is complicated, and I cannot readily interpret it, but it is not just brightness but the presence of UV that can impact coloration.

 

[fredro]

Color and lighting is complicated, and I cannot readily interpret it, but it is not just brightness but the presence of UV that can impact coloration.

Hmm. Back to the drawing board. Thanks for the info!