Does excessive nitrate/ phosphate slow down acropora growth?

jda · Jul 31, 2019

The whole article pretty much says it, but here is a snippet:

Effect of nutrient enrichment The N or P treatments did not result in a significant decrease in growth rate at low concentrations during Period 2 (p = 0.54, p = 0.08). However, the growth rate at high nutrient concentrations during Period 3 was significantly less than in Periods 1 and 2 (p < 0.05).

This is tough since they increased both N and P... but you linked the article... and they introduced co2 as well. Either way, it just goes to show how hard it is to really glean this or that from a study from another ecosystem, even if they are related in a distant way.

This is easy enough to see in our own tank. If you just naturally and slowly lower N and P to NSW type levels, coralline explodes and so does calcification and growth to a level where a tank of 1" frags can all be cantaloupe sized in 30-36 months (not that is always a good thing, especially in small tanks). I do realize that the "slowly" and "naturally" part is they key here and that most people who are against NSW levels probably screwed up one or the other of these and went too fast or used some media wrongly. I just use 3" of sand and real live rock to keep N about .1 and chaeto, lots of skimming and water changes to keep P and 2-3 PPB - I don't really do anything but this.

I do have some abstract thoughts that higher N and P might be good for tanks that use cut-spectrum LED lighting, but these are not well informed and are just thoughts collected from message board posts. If anybody cares to read them, I have them here in posts 15 and 17... take these while a while pile of salt since they are just supposition. I have had some private discussions where people are trying to study this and there might be something to all of this, but it will take a lot of time to figure it all out.

Crunching Numbers at LFS - Radion, Nitrate, Phosphate

Purchased some corals at the LFS today, and took the opportunity to evaluate lighting and nutrients. They use Radion G4s for lighting. PPFD (or PAR, if you will) ranges from 75 to 175 micromole/m2/sec. Photoperiod is 11 hours at this spectral quality: UV-A 2.8% Violet 19.6% Blue 67.8%...

www.reef2reef.com

jda · Jul 31, 2019

I will also say that I have seen many acropora that do not care one bit - these will do well in a tank like the Ross tank with VERY high N and P. However, some will die, stn or just pause with levels just 10x to 20x more than seawater - people consider these the "harder" acropora.

I have to keep my N and P near NSW to get some acropora like Purple Monster, Pink Panther, Simplex and some Echinata (and more) to grow and thrive at a good rate... even slight elevation and the growth nearly stops.

However, I doubt that a Cali Tort, Slimer, MBPS or many others do not mind. These too will grow faster with NSW parameters, but they still grow at a good clip with higher building block levels.

Big E · Aug 1, 2019

jda said:
I will also say that I have seen many acropora that do not care one bit - these will do well in a tank like the Ross tank with VERY high N and P. However, some will die, stn or just pause with levels just 10x to 20x more than seawater - people consider these the "harder" acropora.

I have to keep my N and P near NSW to get some acropora like Purple Monster, Pink Panther, Simplex and some Echinata (and more) to grow and thrive at a good rate... even slight elevation and the growth nearly stops.

However, I doubt that a Cali Tort, Slimer, MBPS or many others do not mind. These too will grow faster with NSW parameters, but they still grow at a good clip with higher building block levels.

These are my same experiences..........I've had high levels PO4 (.30- .5) and all the acros growth slowed, some less than others. There are also a large group that won't grow at all and explode in growth at the most common kept range of .03-.10ppm.

N03 there is a little more wiggle room .5- 10ppm..........it's not so much growth but color is lost or not as vibrant.

The above aren't written in stone but the most common range area.

The levels above are basically the same old school levels that have been successful for decades. Trends for lower levels came about when Zeo entered the market and now it seems people are going to extremes the other way. Either of these extremes showed few long term successes and also few examples.

When levels were ultra low it was Alexander's tank as the poster child...............now Ross's tank is the one example people always point to at the high extremes. Seems everyone forgets about the hundreds of successful reefs that lie right in the same target area that has always worked.

Graffiti Spot · Aug 2, 2019

I think the stability of the nutrient levels as well as the actual nutrient input type matters a lot. I have had much better luck when feeding quality food like algae, home made foods or frozen food over pellets.
But I have seen the same thing with certain species and higher building block levels. If nutrients rise a little there are certain species that show signs there was a change. If the levels spike or continue to rise they stress and others don’t. I don’t believe it’s because some are tank hardened either.