NO3 and PO4 and it's relationship to lighting

[jda]

I wonder if an extremely low N and P (which we measure) reflect extremely low levels of other 'nutrients'/organics that also benefit certain corals.

Probably, right? However, in order to even know we would have to establish a baseline with NSW and then find a way to test. Probably not happening, unfortunately. It seems that we might have to just use N and P as a bellwether for all, which seems to work out Ok for most.

Adding organic carbon for coral benefit was once thought to be a value-add over NSW, but it did not really work out that way with most single cell stuff getting most of it and the light still supplying the corals with carbon through the zoox. This was the hot-take husbandry fad a decade ago like adding N and P is today.

FWIW, I do not consider NSW levels low... just "normal" for where these things come from. Using organic carbon, GFO, LC, etc. to go below this is what I consider low, or what some people call ULNS. After all, the ocean is the only place that these things lived in until half a century ago, and this is the environment that they thrived to live in. I do know that we do not replicate the ocean very much in our little, but doing it where we can does seem to work pretty well.

NSW parameters can be found here:
http://reefkeeping.com/issues/2004-05/rhf/

 

[Bpb]

FWIW I have to use daily vodka dosing AND add LC several times a week just to keep my numbers from spiraling out of control. 4 ml of vodka a day and roughly 40 drops of LC a week keep my phosphates under 0.1 and nitrates under 20 ppm, which itself is pretty high. I know you’re a big proponent of ocean rock, which I have a large amount of. About 1/3 of my rock was added as dry rock 5 years ago, Another 1/3 is roughly 10-12 years old and been in use and live that entire time in reef systems, and the last 1/3 was actual live rock from the ocean

 

[Dana Riddle]

I've mentioned this before in another thread, but photosynthesis is limited by the least available nutrient and not promoted by the most abundant. Liebig's Law of the Minimum.

 

[MnFish1]

I've mentioned this before in another thread, but photosynthesis is limited by the least available nutrient and not promoted by the most abundant. Liebig's Law of the Minimum.

Does that mean that - If nutrients in a tank are 'lower than they should be'- and the Alk and Lighting are 'higher than they should be for that level of nutrients - that this could cause problems? That was my point initially

 

[Oliver d]

Alkalinity and rates of photosynthesis examined through PAM fluorometry.
https://www.advancedaquarist.com/2016/9/aafeature

Very interesting ,learned something new from it

 

[jda]

It can happen with any one of these elements, or another. In most cases in a well-maintained tank, N and P are abundant, carbonate & calcium (and others) are abundant and carbon in lacking (light)... but not always.

For example, in the case of Chaetomorpha, even in a strong environment with an abundance of N, P, light, etc., people who do not change water often, or dose Fe3 (usually), see the Chaeto stop growing or die because there is no more iron in the system. Iron is the growth limiter for it.

Surplus equal abundance in most cases. A really tricky part is that just because you cannot directly test or see one particular resource, does not mean that it is not there (corals getting nitrogen from ammonia/ammonium instead of nitrate, for example). Abundance is not always good. Sometimes it is.

 

[Graffiti Spot]

My favorite topic to read on. I like how jda views it and am happy he continues to try and educate the newer reefers on here by posting his thoughts and experience. A lot of people are going towards using really high nutrient systems and they don’t even understand this stuff.

 

[Dana Riddle]

Here are some nutrient numbers I got when in Hawaii (Kona coast, Big Island of Hawaii.) Determinations were made using Hach reagents (PhosVer 3 for ortho-phosphate aka reactive phosphate & NitraVer 5 for nitrate. This reagent is sensitive to chloride so the nitrate number is lower than actual. A Hach DR-2000 spectrophotometer determined concentrations.)
NO3-N = 3.6 mg/L (or parts per million if you will). Multiply by 4.4 to obtain results as nitrate - 15.84 mg/L. Recall that the cadmium-reduction test procedure under-reports nitrate.
Phosphorus (P) = 0.16 mg/L. Multiply by 3.066 to obtain result as phosphate (PO4 = 0.491 mg/L.)
Why are these results so high? There are multiple reasons. Young volcanic rock contains nitrate, which leaches from the rock with every rainfall. Nitrate and phosphate can be due to migration from cesspools and septic tanks (a sanitary sewer dictated by the EPA had not yet been completed at the time of testing) as well as runoff from fertilized lawns, golf courses, etc.

 

[Graffiti Spot]

Wow, much higher than I would think, even with the variables in mind. Were there corals in that area?

 

[Dana Riddle]

Wow, much higher than I would think, even with the variables in mind. Were there corals in that area?

Oh yeah! Porites (several species), Pocillopora meandrina, P. eydouxi, P. damicornis, and probably a dozen other genera. Hundreds of Yellow Tangs, Convict Tangs and others would come into water less than a foot deep to graze.

 

[Graffiti Spot]

That’s great, I wonder what the other reefs around the world are reading that are in similar situations. I love swimming with fish like that in shallow water.

 

[jda]

The link that I posted above from Dr. Holmes-Farley has seawater values from all over the world. They did tend to stay away from the inhabited shore, IIRC.

 

[Dana Riddle]

The link that I posted above from Dr. Holmes-Farley has seawater values from all over the world. They did tend to stay away from the inhabited shore, IIRC.

An environmental lab specializing in coastal monitoring found nitrates in much higher concentrations in a bay up the Kona coast - it was in the hundreds but I don't recall if it was reported as N or NO3. There were only a few estate houses there (Beach Boys', Dr. Bakken's, etc. estates.) I have no idea why the nitrate was so high. This was relayed to me by the analyst - Karen Kline of Aecos Laboratory. Dr. Bill Walsh (Hawaii DLNR) reported in a paper that nutrients were also high in Kealakekua Bay - I'll try to find that paper.

 

[Reefahholic]

This rule likely doesn’t apply to Sanjay because his N is north of 50 and P sitting around 0.4

Too much N and P is a poison to any organic tissue. The amount varies from creature to creature. Sometimes the effects are linear and sometimes they are exponential. For coral, there is a wide range. Coralline will be seriously hindered at pretty low numbers like around .1p and 2-3P (or so) where it won't quit growing, but will slow quite a bit. Some SPS can handle N up to 50 whereas others will stop growing much at all and even some will STN and die.

Since too much is no good, then adding excess to excess just seems like a bad plan to me. If you have excess then you don't need more excess.

 

[jda]

I saw a paper once that attributed the lack of stonies in the bays and around the islands more to the rising nitrogen levels and less to the clumsy tourists in the water... but it was not a popular narrative for the locals who are quite protective (as you likely know). For the life of me, I cannot remember where I saw that.

I tested water out of Key West, Coral Sea and Tahiti... all were about what Dr. Holmes-Farley wrote his paper about, but Tahiti was a bit colder than the rest... but these are places that can support massive coral reefs (of some sort) moreso that Hawaii. In Hawaii all that we saw was Porites and a few A. Cytheria that were brown and tan - the fish were amazing and the real reason for the snorkel.

 

[Reefahholic]

I saw a paper once that attributed the lack of stonies in the bays and around the islands more to the rising nitrogen levels and less to the clumsy tourists in the water... but it was not a popular narrative for the locals who are quite protective (as you likely know). For the life of me, I cannot remember where I saw that.

I tested water out of Key West, Coral Sea and Tahiti... all were about what Dr. Holmes-Farley wrote his paper about, but Tahiti was a bit colder than the rest... but these are places that can support massive coral reefs (of some sort) moreso that Hawaii. In Hawaii all that we saw was Porites and a few A. Cytheria that were brown and tan - the fish were amazing and the real reason for the snorkel.

Jda, you have some impressive colonies. I know you run MH, but if you were to run T5’s what bulb combination would you run in an 8 bulb fixture? Intensity/photo period?

I tend to keep my LED’s running lower at 20-30% and have my t5’s running at 100% for 4 hours with 1hr ramp periods on both sides.

 

[jda]

Start another thread on this and invite me... would like to keep this one on track as much as we can.

 

[Reefahholic]

Start another thread on this and invite me... would like to keep this one on track as much as we can.

Will do!

 

[Punchanello]

I would turn the LEDs down in that Powermodule... they have not proven to be all that high of quality... best results seem to come with the T5s doing the heavy lifting and the LEDs filtered in for some color and dusk/dawn (I have never used one, so take that FWIW).

Whatever the interaction between very low nutrients, alkalinity and high PAR might be on coral colouration/health, I think you may be on to something here. I most certainly want to at least have detectable NO3 and PO4 although I take your point about availability rather than quantity. Given the way I feed and the fact that I run my Alkalinity on the low side I don't think availability of nutrients is the issue (at least not now that my fish are back).

I looked over my tank with the lighting in mind last night.

I notice a few things. Light dispersion across the tank is pretty good with or without the LEDs. In fact, maybe too good for some corals. For example I had an un-shadowed cyphastrea looking pale on the bottom of the tank, but I moved it under some shade and it is doing much better and colouring up. My acros that are fully exposed to light but at the bottom third or half of the tank are doing quite well and have great colour. Nothing on the bottom of my tank is doing poorly.

What I just realised is the SPS sitting on the highest shelves along the central axis of the tank are pretty much all pale. Those at the same height but towards the outer edges (front or back) are looking healthy and colouring up nicely despite being directly under the T5s. The ATI Powermodule LEDs have no lenses to disperse light and run in a thin strip along the centre of the tank. This means that at the highest points of the rock work these lights would be blasting directly on a very narrow piece of real estate and very little else. I have also lost a number of corals in those areas over time. I'm thinking it may very well be the LEDs that are a problem.

 

[LARedstickreefer]

I wonder if led blend is a problem? If the leds are too close to the water surface, and thus the corals, they won’t blend as well as if they were much higher up. So, instead of a particular spot on the coral getting an even blend of all of the led fixture colors, it’s just getting one.

For example: At maybe 12in up, a coral gets blues, reds, greens, and whites. At 6in up the same coral now only gets say green and some blue.