Why is phosphate "bad"?

[Murraydar]

Common knowledge in this hobby is that elevated po4 levels is bad for corals, leading to algae, slow growth, improper calcification, death, etc. But when I look for hard evidence of this I find nothing. In fact, many successful tanks I see have elevated levels that do just fine.

Anyone have any good studies or papers that can give more info? Thanks.

 

[Randy Holmes-Farley Verified Community Expert]

Elevated nutrients can brown up many corals from elevated zoox levels, can spur algae growth, and is reported in the scientific literature to slow calcification.

Each of those may be able to be overcome in other ways, and too low of nutrients has its own problems, maybe worse ones.

 

[Randy Holmes-Farley Verified Community Expert]

Here, for example, suggesting reduced growth:
Effects of elevated nitrogen and phosphorus on coral reef growth


https://aslopubs.onlinelibrary.wiley.com/doi/abs/10.4319/lo.1979.24.5.0935

 

[jeffmr4]

What are the worse ones of too low nutrients?

 

[kecked]

Dinoflagellates to start. Trust me you don’t want them. Poor color poor growth. Really hungry cleanup crew that the eats your coral. Emerald crabs that turn white. Dead clams. Dead sponges......I lived all this.
I had zero N and zero P. Alk 9 mg 1350 ca 450 thought I was king....yea no.

 

[Murraydar]

Elevated nutrients can brown up many corals from elevated zoox levels, can spur algae growth, and is reported in the scientific literature to slow calcification.

Each of those may be able to be overcome in other ways, and too low of nutrients has its own problems, maybe worse ones.

Thanks for the article, was a good read.

Any idea why it slows calcification?

Dinoflagellates to start. Trust me you don’t want them. Poor color poor growth. Really hungry cleanup crew that the eats your coral. Emerald crabs that turn white. Dead clams. Dead sponges......I lived all this.
I had zero N and zero P. Alk 9 mg 1350 ca 450 thought I was king....yea no.

I've had everything you listed in the past year with my tank. Always thought nutrients were killing my corals, so I did everything in my power to reduce them. About a month or so ago, after doing loads of research into coral nutrition, I basically stopped all effeorts to remove nutrients.

For a few weeks the only piece of equipment filtering my water is a turf scrubber that im running light to keep nutrients up. All my dino went away, polyp extension is back, corals are calcifying again, pod populations are exploding. Ridiculous hobby.

 

[kecked]

Yea everything I thought is wrong! Let it alone and stop messing and nature actually works. Still fighting dinos but much better. I’m doing a study in my coolia Dino to see if I can measure the toxin in the water or even in centrifuge spun cells. Nothing yet. Looking to desorb my carbon next.

 

[Luno]

You can successfully run ULNS given you understand how to do it. And it can be a very efficient way to keep problem algae away.

The other thing is when people say they have zero P, it is the single most doubted measurement in the hobby IMO. Unless you measure it with Hanna instrument it is very difficult to accurate measure in color change tests even with good brands like Red Sea or saifert. They simply don't low rank measure accurately enough

 

[kecked]

I did it for twenty years but I like this new approach. Even with dinos everything looks better. My tank is sooo sterile beyond nitrobacter and such I got squat. No green algae no diatoms. Nothing. Just coolia dinos. Still need to do rock scrapes. It isn’t in the water however.

 

[Randy Holmes-Farley Verified Community Expert]

Thanks for the article, was a good read.

Any idea why it slows calcification?

I discuss a likely hypothesis here:

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

Calcification Inhibition by Phosphate

One important issue relating to elevated phosphate in reef aquaria has to do with the inhibition of calcification by phosphate and phosphate-containing organics. Phosphate is known to inhibit the precipitation of calcium carbonate from seawater. The presence of phosphate in the water also decreases calcification in corals, such as Pocillopora damicornis and entire patch reefs. This inhibition is likely related to the presence of phosphate in the extracytoplasmic calcifying fluid (ECF), where calcification takes place in corals, and on the growing crystal’s surface. Exactly how the phosphate gets into the ECF isn’t well understood.

This inhibition of calcification takes place at concentrations frequently attained in reef aquaria and may begin at levels below those detectable by hobby test kits. For example, one research group found that long-term enrichment of phosphate (0.19 ppm; maintained for three hours per day) on a natural patch reef on the Great Barrier Reef inhibited overall coral calcification by 43%. A second team found effects in several Acropora species at similar concentrations.

Organic phosphate and phosphonate inhibitors of calcification have also been studied and probably work by a similar mechanism. Etidronate, a bisphosphonate that is used to treat osteoporosis (Figure 3), caused a 36% inhibition of calcification inStylophora pistillata at 2 ppm, and stopped it completely (99%) at 100 ppm, while photosynthesis was not affected at these, and higher, concentrations (indicating it is not a general toxin).9

With all this said, however, there are a few very nice reef aquaria that have exceptionally high phosphate, up to 2 ppm. Thislinked article has more details. Presumably, pest algae in these aquaria are inhibited by something other than low nutrients, and iron is a likely candidate. How such systems get around the inhibition of calcification is unclear, but apparently they can.

 

[becks]

Emerald crabs that turn white.

When I got my emerald crab his body was white, I asked on here and no one really answered. But when I first got him he did pick on my Duncan’s.....now he’s green all over and I’ve never seen him pick at a coral since.

 

[Randy Holmes-Farley Verified Community Expert]

When I got my emerald crab his body was white, I asked on here and no one really answered. But when I first got him he did pick on my Duncan’s.....now he’s green all over and I’ve never seen him pick at a coral since.

Wrong thread???

 

[becks]

Wrong thread???

Just replying to part of a comment made in this thread

 

[Randy Holmes-Farley Verified Community Expert]

Just replying to part of a comment made in this thread

Oh, I see it now. I’ve seen that reported many times. I don’t know what it is, but I suspect it is a dietary thing as opposed to phosphate in the water.

 

[Hans-Werner]

Recent research shows that phosphate doesn´t slow coral growth but increases skeletal growth. The skeleton formed under elevated phosphate concentrations is lighter, less sturdy and more fragile. The reason for these observations might be that phosphate is integrated in the organic skeletal matrix. When more skeletal matrix is formed at the same or only slightly increased calcification rate the skeletal growth is faster but the formed skeleton is lighter.