No Nitrates

[DrufusReef]

So I don't know if this is a problem or not, I have always had undetectable nitrates, but I have had elevated phosphates and the algae problem that goes with it. With hard work I've brought my phosphate level down(and algae along with it), but I've still never seen a raise in my nitrates. Looking at testing sites that seems like a good thing, but I've seen posts that nitrates are needed for softy and SPS coral. Is this true? My phosphate is down to 0.025 and I just did a 20g water change today(130g system). I know softies will suck some of that up. Should I be trying to get my nitrates up? Should I also keep a small amount of phosphate for my softies to eat?

 

[jda]

Corals need some nitrogen. They don't have to get it from nitrate. First, you likely have nitrate or else you would have no algae and the corals that you would not grow. Second, nitrogen from ammonia and ammonium are a great way for corals to get nitrogen. Nitrogen that is available to the corals is more important than nitrate on the back end. Keep on feeding and they will be more than fine. Even .1 of nitrate is enough if you have nitrogen moving through the system from feeding the fish and letting them turn it into pee and poo.

BTW - N and P are not food. They are building blocks of organic tissue. Food comes from the sugars that the zoox makes and if your corals can catch anything with carbon in it (so variable depending on tank and coral type).

 

[DrufusReef]

Corals need some nitrogen. They don't have to get it from nitrate. First, you likely have nitrate or else you would have no algae and the corals that you would not grow. Second, nitrogen from ammonia and ammonium are a great way for corals to get nitrogen. Nitrogen that is available to the corals is more important than nitrate on the back end. Keep on feeding and they will be more than fine. Even .1 of nitrate is enough if you have nitrogen moving through the system from feeding the fish and letting them turn it into pee and poo.

BTW - N and P are not food. They are building blocks of organic tissue. Food comes from the sugars that the zoox makes and if your corals can catch anything with carbon in it (so variable depending on tank and coral type).

This is very helpful. Thank you

 

[Crustaceon]

You really don’t need that much nitrate as long as you keep food rolling into the tank and quickly exported out to prevent it from breaking down. The reason a lot of us like to keep it high is because it provides a “safety net” for our corals. One of the worst things that can happen to coral is having nitrates, and especially phosphates bottom out. Having that reserve gives the reefer a better chance to detect a negative trend and correct it. The downside is typically slower growth, possible worse coloration and in less established systems, nuisance algae.

 

[DrufusReef]

You really don’t need that much nitrate as long as you keep food rolling into the tank and quickly exported out to prevent it from breaking down. The reason a lot of us like to keep it high is because it provides a “safety net” for our corals. One of the worst things that can happen to coral is having nitrates, and especially phosphates bottom out. Having that reserve gives the reefer a better chance to detect a negative trend and correct it. The downside is typically slower growth, possible worse coloration and in less established systems, nuisance algae.

Now is that based on SPS? I don't plan on having any sps

 

[jda]

I don't keep many softies and LPS, but I do have some eclectus, bounce and jawbreaker mushrooms, some more fun Z&P, Colorado Sunbursts and a few rainbow chalices and they all do very well in the same water that my acropora thrive in. All of these grow as fast as anybody else.

IMO, dirty and clean water designations are lazy and inaccurate. Some corals can tolerate things that others cannot and some even do quite well, but all of them thrive with water with natural ish parameters.

 

[Timfish]

Nitrogen that corals use can be organic particulates (bugs and stuff like the nitrogen rich detritus from cryptic sponges) or it can be in the form of Dissolved Organic Nitrogen (DON) which included amino acids and urea from animals or it can be in the form of Dissolved Inorganic Nitrogen (DIN) which includes ammonia/ammonium and nitrate. Corals also have symbiotic diazotrophs which fix N2 (nitrogen dissolved in water) which may be a source for corals. But dosing nitrates has it's risks and can be one of the factors in bleaching as well as having negative effects on calcification. Here's a video by some of the researchers working with corals and some additional links if you're interested.

Diazotrophs: a non-negligible source of nitrogen for the tropical coral Stylophora pistillata - PubMed

Corals are mixotrophs: they are able to fix inorganic carbon through the activity of their symbiotic dinoflagellates and to gain nitrogen from predation on plankton and uptake of dissolved organic and inorganic nutrients. They also live in close association with diverse diazotrophic communities...

pubmed.ncbi.nlm.nih.gov

Water quality and coral bleaching thresholds: Formalising the linkage for the inshore reefs of the Great Barrier Reef, Australia

The threats of wide-scale coral bleaching and reef demise associated with anthropogenic climate change are widely known. Here, the additional role of …

www.sciencedirect.com

Uptake of dissolved free amino acids by the scleractinian coral Stylophora pistillata | Journal of Experimental Biology | The Company of Biologists

jeb.biologists.org

Urea uptake by the scleractinian coral Stylophora pistillata

Urea can be one of the major sources of nitrogen for phytoplankton, but little is known about its importance for corals. Experiments were therefore de…

www.sciencedirect.com

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onlinelibrary.wiley.com

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[Crustaceon]

Now is that based on SPS? I don't plan on having any sps

It’s pretty much the same for softies, lps and sps. You always hear zoas doing awesome in “dirty” water, but they also do great in very low nitrate and phosphate environments if provided a steady supply of food like reefroids etc.

 

[jda]

To add onto the above forms of particulate/DON nitrogen above, I have been reading a lot about bacteria in the ocean/tank thanks to my new online friend flampton piquing my interest. Most corals with a slime coat can catch bacteria and assimilate nearly all of that energy though the slime directly - this is in contrast with "food" caught in polyps that need to be "digested" at a higher cost without knowing if the caught energy was worth the effort. This is a math problem for corals that is hard to win, but they do better eventually - the surface area of small corals and frags is almost a rounding error in our tanks compared to the sand, rocks and water column, but larger stuff has a better chance to catch more with more surface area. Counts in the ocean are significantly higher than in our tanks where we filter a LOT. Flow matters a lot where too much can create a shield around a coral to allow less catching - evidence of this is pretty sparse, but it seems legit where way too much flow is not good, like many have opined that have experience with just trying to have more flow than the next guy.