Can high phosphate inhibit algae?

[Subsea]

OK, thanks. I'll get an ICP-MS test and meanwhile use and learn how to regenerate GFO as soon as it gets here.

Since very little algae is growing, could the iron I've been adding go anywhere besides precipitating? Would my high alk of 11.3 make precipitating iron more likely?

The issue I have with the cocktail approach is my levels of zinc, lithium and other stuff are already too high.

Good to know there is a more high powered ICP! Thank you!

High alkalinity with high pH can generate a snow storm.

Once, while dosing iron in a 55G Gracilaria Hayi seaweed grow out tank, I spilled 50ml of concentrate ferric solution. Tank water turned red where I couldn’t see back glass for 2 days. When water cleared up, I noted raised section on Hayi surfaces and texture changed from slightly calcified to rubbery & flexible. After 2 weeks with only dosing ammonia, Hayi returned to normal texture. I recalled an article written by @Randy Holmes-Farley describing seaweed storage mechanism for iron. I don’t doubt there is a similar process for phosphate. Go figure.

 

[salty joe]

Interesting.

My pH tends to be kind of low, it's 7.95 right now.

 

[Randy Holmes-Farley]

OK, thanks. I'll get an ICP-MS test and meanwhile use and learn how to regenerate GFO as soon as it gets here.

Since very little algae is growing, could the iron I've been adding go anywhere besides precipitating? Would my high alk of 11.3 make precipitating iron more likely?

The issue I have with the cocktail approach is my levels of zinc, lithium and other stuff are already too high.

Good to know there is a more high powered ICP! Thank you!

All tank organisms use iron, but precipitation is a known sink as well.

 

[Hans-Werner]

Very interesting discussion that contradicts the image that a high phosphate reef tank should be full of algae and have a lot of algal growth.

This weekend I was at an event (Vivarium/MACE in Rosmalen/Netherlands) where a reefer reported good coral growth and a beautiful reef tank at 4.5(!) ppm phosphate to me. Of course all his reefer friends told him this can't be, and so he lowered phosphate concentration because he got unsure and didn't want to be the freak.

 

[salty joe]

Here's the ICP MS result. I topped off manganese and molybdenum and added enough iron EDDHA 6% to increase iron by 0.5 ug/l. I'm hoping this highly chelated form of iron makes a difference for algae growth. Not sure what a safe limit is for how much and how often to dose this iron. Any guidance there would be appreciated.

The high magnesium and sulfur is odd, I have not used mag mix with Epsom salt for years. The only dosing I do are kalk and specific elements. And home grown phyto, Nanno.

I know my nutrients are through the roof but the fish seem fine, the clowns continue to lay eggs. Fingers crossed algae starts growing again and I can get things trending in the right direction.

Base elements

Sal. total
Salinity
34.37 PSU
Ideal value: 35.00 PSU
NORMAL
Near nature

KH
Carbonate hardness
10.27 °dKH
Ideal value: 7.50 °dKH
CRITICALLY HIGH
Critical
Major elements

Cl
Chloride
18539 mg/l
Ideal value: 18947 mg/l
NORMAL
Near nature

Na
Sodium
10753 mg/l
Ideal value: 10526 mg/l
NORMAL
Near nature

Mg
Magnesium
1415 mg/l
Ideal value: 1258 mg/l
ABOVE NORMAL
Attention

S
Sulfur
1089 mg/l
Ideal value: 870.8 mg/l
CRITICALLY HIGH
Critical

Ca
Calcium
487.4 mg/l
Ideal value: 402.9 mg/l
CRITICALLY HIGH
Critical

K
Potassium
427.1 mg/l
Ideal value: 390.4 mg/l
ABOVE NORMAL
Attention

Br
Bromine
78.03 mg/l
Ideal value: 64.11 mg/l
ABOVE NORMAL
Attention

Sr
Strontium
7.74 mg/l
Ideal value: 7.75 mg/l
NORMAL
Near nature

B
Boron
4.59 mg/l
Ideal value: 4.31 mg/l
NORMAL
Near nature

F
Fluorine
0.96 mg/l
Ideal value: 1.24 mg/l
NORMAL
Near nature
Minor elements

Li
Lithium
543.9 µg/l
Ideal value: 162.7 µg/l
ABOVE NORMAL
Attention

Si
Silicon
258.6 µg/l
Ideal value: 95.69 µg/l
NORMAL
Near nature

I
Iodine
127.1 µg/l
Ideal value: 62.20 µg/l
ABOVE NORMAL
Attention

Ba
Barium
6.354 µg/l
Ideal value: 9.57 µg/l
NORMAL
Near nature

Mo
Molybdenum
9.581 µg/l
Ideal value: 11.48 µg/l
NORMAL
Near nature

Ni
Nickel
0.305 µg/l
Ideal value: 0.48 µg/l
NORMAL
Near nature

Rb
Rubidium
131.9 µg/l
Ideal value: 124.4 µg/l
NORMAL
Near nature

Mn
Manganese
0.137 µg/l
Ideal value: 0.96 µg/l
BELOW NORMAL
Attention

As
Arsenic
28.05 µg/l
Ideal value: 0.48 µg/l
CRITICALLY HIGH
Critical

Be
Beryllium
< 0.00 µg/l
Ideal value: 0.10 µg/l
NORMAL
Near nature

Cr
Chrome
0.095 µg/l
Ideal value: 0.48 µg/l
NORMAL
Near nature

Co
Cobalt
0.088 µg/l
Ideal value: 0.10 µg/l
NORMAL
Near nature

Fe
Iron
< 0.20 µg/l
Ideal value: 0.48 µg/l
BELOW NORMAL
Attention

Cu
Copper
0.341 µg/l
Ideal value: 0.48 µg/l
NORMAL
Near nature

Se
Selenium
0.382 µg/l
Ideal value: 0.48 µg/l
NORMAL
Near nature

Ag
Silver
< 0.02 µg/l
Ideal value: 0.10 µg/l
NORMAL
Near nature

V
Vanadium
3.176 µg/l
Ideal value: 1.44 µg/l
NORMAL
Near nature

Zn
Zinc
10.10 µg/l
Ideal value: 1.91 µg/l
CRITICALLY HIGH
Critical

Sn
Tin
< 0.07 µg/l
Ideal value: 0.48 µg/l
NORMAL
Near nature
Nutrients

NO3
Nitrate
227.0 mg/l
Ideal value: 2.00 mg/l
CRITICALLY HIGH
Critical

P
Phosphorus
1223 µg/l
Ideal value: 14.35 µg/l
CRITICALLY HIGH
Critical

PO4
Phosphate
3.75 mg/l
Ideal value: 0.04 mg/l
CRITICALLY HIGH
Critical

Pollutants

Al.
Aluminium
4.724 µg/l
Ideal value: 0.10 µg/l
NORMAL
Near nature

Sb
Antimony
1.087 µg/l
Ideal value: 0.10 µg/l
NORMAL
Near nature

Bi
Bismuth
< 0.01 µg/l
Ideal value: 0.10 µg/l
NORMAL
Near nature
Pb

Lead
< 0.02 µg/l
Ideal value: 0.10 µg/l
NORMAL
Near nature

Cd
Cadmium
0.068 µg/l
Ideal value: 0.19 µg/l
NORMAL
Near nature

La.
Lanthanum
< 0.01 µg/l
Ideal value: 0.001 µg/l
NORMAL
Near nature

Tl
Thallium
< 0.02 µg/l
Ideal value: 0.10 µg/l
NORMAL
Near nature

Ti
Titanium
0.075 µg/l
Ideal value: 0.10 µg/l
NORMAL
Near nature

Nb
Niobium
< 0.07 µg/l
Ideal value: 0.001 µg/l
NORMAL
Near nature

Nd
Neodym
0.004 µg/l
Ideal value: 0.001 µg/l
NORMAL
Near nature

Zr
Zirconium
0.121 µg/l
Ideal value: 0.001 µg/l
NORMAL
Near nature

Ge
Germanium
0.094 µg/l
Ideal value: 0.001 µg/l
NORMAL
Near nature

Ga
Gallium
0.155 µg/l
Ideal value: 0.001 µg/l
NORMAL
Near nature

W
Tungsten
0.139 µg/l
Ideal value: 0.001 µg/l
NORMAL
Near nature

Hg
Mercury
0.324 µg/l
Ideal value: 0.001 µg/l
NORMAL
Near nature

Te
Tellur
< 0.00 µg/l
Ideal value: 0.001 µg/l
NORMAL

 

[Subsea]

Here's the ICP MS result. I topped off manganese and molybdenum and added enough iron EDDHA 6% to increase iron by 0.5 ug/l. I'm hoping this highly chelated form of iron makes a difference for algae growth. Not sure what a safe limit is for how much and how often to dose this iron. Any guidance there would be appreciated.

The high magnesium and sulfur is odd, I have not used mag mix with Epsom salt for years. The only dosing I do are kalk and specific elements. And home grown phyto, Nanno.

I know my nutrients are through the roof but the fish seem fine, the clowns continue to lay eggs. Fingers crossed algae starts growing again and I can get things trending in the right direction.

Base elements

Sal. total
Salinity
34.37 PSU
Ideal value: 35.00 PSU
NORMAL
Near nature

KH
Carbonate hardness
10.27 °dKH
Ideal value: 7.50 °dKH
CRITICALLY HIGH
Critical
Major elements

Cl
Chloride
18539 mg/l
Ideal value: 18947 mg/l
NORMAL
Near nature

Na
Sodium
10753 mg/l
Ideal value: 10526 mg/l
NORMAL
Near nature

Mg
Magnesium
1415 mg/l
Ideal value: 1258 mg/l
ABOVE NORMAL
Attention

S
Sulfur
1089 mg/l
Ideal value: 870.8 mg/l
CRITICALLY HIGH
Critical

Ca
Calcium
487.4 mg/l
Ideal value: 402.9 mg/l
CRITICALLY HIGH
Critical

K
Potassium
427.1 mg/l
Ideal value: 390.4 mg/l
ABOVE NORMAL
Attention

Br
Bromine
78.03 mg/l
Ideal value: 64.11 mg/l
ABOVE NORMAL
Attention

Sr
Strontium
7.74 mg/l
Ideal value: 7.75 mg/l
NORMAL
Near nature

B
Boron
4.59 mg/l
Ideal value: 4.31 mg/l
NORMAL
Near nature

F
Fluorine
0.96 mg/l
Ideal value: 1.24 mg/l
NORMAL
Near nature
Minor elements

Li
Lithium
543.9 µg/l
Ideal value: 162.7 µg/l
ABOVE NORMAL
Attention

Si
Silicon
258.6 µg/l
Ideal value: 95.69 µg/l
NORMAL
Near nature

I
Iodine
127.1 µg/l
Ideal value: 62.20 µg/l
ABOVE NORMAL
Attention

Ba
Barium
6.354 µg/l
Ideal value: 9.57 µg/l
NORMAL
Near nature

Mo
Molybdenum
9.581 µg/l
Ideal value: 11.48 µg/l
NORMAL
Near nature

Ni
Nickel
0.305 µg/l
Ideal value: 0.48 µg/l
NORMAL
Near nature

Rb
Rubidium
131.9 µg/l
Ideal value: 124.4 µg/l
NORMAL
Near nature

Mn
Manganese
0.137 µg/l
Ideal value: 0.96 µg/l
BELOW NORMAL
Attention

As
Arsenic
28.05 µg/l
Ideal value: 0.48 µg/l
CRITICALLY HIGH
Critical

Be
Beryllium
< 0.00 µg/l
Ideal value: 0.10 µg/l
NORMAL
Near nature

Cr
Chrome
0.095 µg/l
Ideal value: 0.48 µg/l
NORMAL
Near nature

Co
Cobalt
0.088 µg/l
Ideal value: 0.10 µg/l
NORMAL
Near nature

Fe
Iron
< 0.20 µg/l
Ideal value: 0.48 µg/l
BELOW NORMAL
Attention

Cu
Copper
0.341 µg/l
Ideal value: 0.48 µg/l
NORMAL
Near nature

Se
Selenium
0.382 µg/l
Ideal value: 0.48 µg/l
NORMAL
Near nature

Ag
Silver
< 0.02 µg/l
Ideal value: 0.10 µg/l
NORMAL
Near nature

V
Vanadium
3.176 µg/l
Ideal value: 1.44 µg/l
NORMAL
Near nature

Zn
Zinc
10.10 µg/l
Ideal value: 1.91 µg/l
CRITICALLY HIGH
Critical

Sn
Tin
< 0.07 µg/l
Ideal value: 0.48 µg/l
NORMAL
Near nature
Nutrients

NO3
Nitrate
227.0 mg/l
Ideal value: 2.00 mg/l
CRITICALLY HIGH
Critical

P
Phosphorus
1223 µg/l
Ideal value: 14.35 µg/l
CRITICALLY HIGH
Critical

PO4
Phosphate
3.75 mg/l
Ideal value: 0.04 mg/l
CRITICALLY HIGH
Critical

Pollutants

Al.
Aluminium
4.724 µg/l
Ideal value: 0.10 µg/l
NORMAL
Near nature

Sb
Antimony
1.087 µg/l
Ideal value: 0.10 µg/l
NORMAL
Near nature

Bi
Bismuth
< 0.01 µg/l
Ideal value: 0.10 µg/l
NORMAL
Near nature
Pb

Lead
< 0.02 µg/l
Ideal value: 0.10 µg/l
NORMAL
Near nature

Cd
Cadmium
0.068 µg/l
Ideal value: 0.19 µg/l
NORMAL
Near nature

La.
Lanthanum
< 0.01 µg/l
Ideal value: 0.001 µg/l
NORMAL
Near nature

Tl
Thallium
< 0.02 µg/l
Ideal value: 0.10 µg/l
NORMAL
Near nature

Ti
Titanium
0.075 µg/l
Ideal value: 0.10 µg/l
NORMAL
Near nature

Nb
Niobium
< 0.07 µg/l
Ideal value: 0.001 µg/l
NORMAL
Near nature

Nd
Neodym
0.004 µg/l
Ideal value: 0.001 µg/l
NORMAL
Near nature

Zr
Zirconium
0.121 µg/l
Ideal value: 0.001 µg/l
NORMAL
Near nature

Ge
Germanium
0.094 µg/l
Ideal value: 0.001 µg/l
NORMAL
Near nature

Ga
Gallium
0.155 µg/l
Ideal value: 0.001 µg/l
NORMAL
Near nature

W
Tungsten
0.139 µg/l
Ideal value: 0.001 µg/l
NORMAL
Near nature

Hg
Mercury
0.324 µg/l
Ideal value: 0.001 µg/l
NORMAL
Near nature

Te
Tellur
< 0.00 µg/l
Ideal value: 0.001 µg/l
NORMAL

You can’t overdose iron or silicates; they will precipitate out.

Macro algae will sequester heavy metals

 

[Randy Holmes-Farley]

I would not generally use a strongly chelated iron for iron dosing since somehow organisms that need iron need to strip off the chelator. It is known that chelators can reduce the bioavailability of metals. Treatments of metal overdose use chelators for this reason.

That is why I recommend weakly chelated iron such as ferrous gluconate for dosing.

 

[Subsea]

I read the whole thing and it was quite detailed. The graph above was for one species only:

“L. intricata, growth rates varied significantly with tissue %P (ANOVA, F(7,25) = 2.975, P = 0.029) in a unimodal relationship with peak growth attained in algae with tissue P concentrations of 0.21% (Fig. 6).”

However, the other Macroalgaes in the study did not reflect stunted growth with very high phosphate. The excess uptake of this group was called “luxury” uptake to be used later when phosphate was low in the water column. Similar to iron storage to be used when iron was low in water column.

First sentence of first paragraph in discussion section:

“Elevating nutrient levels did not result in increased growth rates in any of the macroalgal species in our experiments. However, the algae did respond positively in other ways to nutrient additions, which contradicts the possibility of nutrient toxicity.”

High Nitrogen and Phosphorous Acquisition by Belowground Parts of Caulerpa prolifera (Chlorophyta) Contribute to the Species' Rapid Spread in Ria Formosa Lagoon, Southern Portugal - PubMed

Despite worldwide proliferation of the genus Caulerpa and subsequent effects on benthic communities, little is known about the nutritional physiology of the Caulerpales. Here, we investigated the uptake rates of ammonium, nitrate, amino acids, and phosphate through the fronds and rhizoids +...

pubmed.ncbi.nlm.nih.gov

I was just made aware of the difference in nutrient uptake of submerged holdfast of Caulerpa Prolifera compared to uptake of fronds:

First, submerged portion sequestered both organic & inorganic phosphorus & nitrogen.

Second, the ratio of phosphate to nitrate was higher in submerged portion than fronds in bulk water.

In an associated peer reviewed article I found out why I failed at cultivating Sea Grapes, Caulerpa Lentillifera. Sea Grapes prefer nitrate to ammonia.

 

[Hans-Werner]

I would not generally use a strongly chelated iron for iron dosing since somehow organisms that need iron need to strip off the chelator. It is known that chelators can reduce the bioavailability of metals. Treatments of metal overdose use chelators for this reason.

That is why I recommend weakly chelated iron such as ferrous gluconate for dosing.

Exactly what I also thought!

EDTA also is a weaker chelator. Its complexes with iron are said to decay in the light and form again in the dark. Reduction of smaller iron(III) ions to larger iron(II) ions also weakens the complexes and facilitates decay.

 

[salty joe]

I turned off the stirrer for my kalk reactor, hopefully the kalk will be less concentrated and Ca and KH will drop. I'm gonna wait for a week or so and see if hair algae starts growing in the fuge and go from there.

Strictly concerning overdose, how does strongly chelated iron like EDDHA compare to glucanate?

 

[Randy Holmes-Farley]

I turned off the stirrer for my kalk reactor, hopefully the kalk will be less concentrated and Ca and KH will drop. I'm gonna wait for a week or so and see if hair algae starts growing in the fuge and go from there.

Strictly concerning overdose, how does strongly chelated iron like EDDHA compare to glucanate?

The issue for strong chelation is the iron will be there but may be less usable or unusable until something breaks it apart, such as a uv.

 

[salty joe]

A week after adding eddha 6% to boost iron by 0.5 ug/l, nuisance algae started growing but the tint went away. So I added another 0.3 ug/l. The water is tinted but I'm OK with that for now, it's actually nice because I can visually tell when to add more. When I was adding that much glucanate, nothing was happening. IDK, but I think the crazy high phosphate was causing the glucanate to precipitate. I found very little info on using eddha in a marine tank. Everything seems fine, clowns still laying eggs.

Have not got my hands on chaeto yet, fingers crossed.