What level of nitrate harms corals?

[Ocean Lotion]

I went bare bottom and for the first time in 20 years of reefing I have detectable nitrates. I noticed my monti cap is not happy. My nitrate measured at 50 ppm. At what level are sps harmed bt nitrate?

 

[mcarroll]

None, really – don't panic. Something else is going on and we can figure it out.

"Harmful" only seems to happen with nitrates when the situation loses balance....not at a certain level. It's a nutrient, not a toxin.

Most of the time that trouble happens specifically when phosphate becomes unavilable (due to being used up), but there are other scenarios.

What are your tests for phosphate like?

What else are you doing for/against your nutrients? Any carbon dosing? Any GFO use? Etc?

 

[Ocean Lotion]

I am not sure what is going on. Going to cover the basics first. Multiple water changes and change back filter media. My alk is up to 10.7 and ca is 480. Will slowly drop alk back down. Only tI'm I have seen monti cap look like this is when my ca was too low for a while.

 

[mcarroll]

Do you have a phosphate test?

 

[Ocean Lotion]

Did a 5 gal water change tiday. Will be testing po4 later. Corals look better already.

 

[acro-ed]

There is a relationship between Nutrients, Light intensity, and Alk as to what is "safe." Seemingly (and unscientifically), you can have a lot or a little of all three, but once one goes dis-proportionally high there are problems.

Ex. High nutrient, high light, low alk = slower growth and darker/brown zooxanthellae.

Ex. Low nutrient, high light, high alk = tip burn, paler zoox.

Ex. High nutrient, high light, high alk = color and growth

"Nutrient" as a catch all, to me, really just means NO3 and PO4, which should, ideally, be balanced at 21:1 (value of N to P in zooxanthellae; see also "redfield" ratio noted as 16:1 which is based on plankton composition), but also up-taken relative to available Carbon.

I'm not saying to strive for this ratio (just keep it in mind), but if Nitrates are "high" and phosphate "too low" then your corals may not be able to consume the nutrients properly. People also notice this with macroalgae in their refugiums.... some may say, "I have high phosphate but my cheato isn't growing"; the answer is probably that the available nitrates are too low.


TL;DR = I keep my Nitrates around 25 and get great growth and color with my SPS; when they go much past 40 both start to suffer (Note: all tanks are different depending on light and Alk).

-Ed

 

[Ocean Lotion]

There is a relationship between Nutrients, Light intensity, and Alk as to what is "safe." Seemingly (and unscientifically), you can have a lot or a little of all three, but once one goes dis-proportionally high there are problems.

Ex. High nutrient, high light, low alk = slower growth and darker/brown zooxanthellae.

Ex. Low nutrient, high light, high alk = tip burn, paler zoox.

Ex. High nutrient, high light, high alk = color and growth

"Nutrient" as a catch all, to me, really just means NO3 and PO4, which should, ideally, be balanced at 21:1 (value of N to P in zooxanthellae; see also "redfield" ratio noted as 16:1 which is based on plankton composition), but also up-taken relative to available Carbon.

I'm not saying to strive for this ratio (just keep it in mind), but if Nitrates are "high" and phosphate "too low" then your corals may not be able to consume the nutrients properly. People also notice this with macroalgae in their refugiums.... some may say, "I have high phosphate but my cheato isn't growing"; the answer is probably that the available nitrates are too low.


TL;DR = I keep my Nitrates around 25 and get great growth and color with my SPS; when they go much past 40 both start to suffer (Note: all tanks are different depending on light and Alk).

-Ed

Thanks. I have seen swings in which corals are doing well in my tanks and it was always correlated to changes in nuetrients, lighting and hubandry. It is interesting to me to have detectible NA for the fort time. Something new to play with.

 

[Servillius]

I vaguely remember 30 years ago the general advice being aim for 20ppm, 40ppm tops. It’s funny to think we’re back there.

My preference is still for lower nitrates, but stability is key. What @mcarroll says!

 

[Docdiggy]

I've been dealing with no nutrients. Well at least my tests say so. I've been dosing sodium nitrate for the last 2 weeks and they're about 2ppm. My hanna reads 0 phos though. Ever since I ditched my old sump which was probably a nutrient pit, reef keeping has been very unsatisfying. Non stop struggle.

 

[Ellery]

Yeah I also have found that when my 420 gallon system was running too lean stuff starts to get pale and some tissues start receding. I've been dosing potassium nitrate (spectracide stump remover) to attempt to get to 2ppm and have reduced my biopellet run to only every 3 hours. My PO4 has been at 0.03ppm which is what I prefer for my sps dominant system.


I also observed that with higher alk > 10 dkh and low nutrients I will see rtn/stn occur on my acros so I feed more.

The parameters I've been seeing a lot of people target are 2-5ppm NO3 and 0.02-0.05ppm PO4. With alk/ca/mg at natural seawater levels.
At today's tightly sealed homes to achieve pH closer to 8.2 I also use kalk in my ATO along plain ro water pending alk and pH levels.