Phosphate: How much is too much and do you even worry about it?

BRS

Do you try to keep your phosphates at a certain level besides zero?

  • Yes (please tell us what in the thread)

    Votes: 275 56.9%
  • No I try to keep mine at zero

    Votes: 47 9.7%
  • I don't worry about phosphate levels

    Votes: 144 29.8%
  • Other (please explain)

    Votes: 17 3.5%

  • Total voters
    483

mrlavalamp

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Currently my tank is at .8, very little algae though and some corals un happy but not overly so.

I was around .25 to .5 and everything seemed great for several months so I stopped checking. Oops.

Recently had my elegance start shrinking up (no other signs of ecs though, thank God) and my gonis not opening all the way. Otherwise everything seems happy, and not much algae in my tank. Tested and phosphate was 1.0+ on my red sea test. Wasn't satisfied with red sea so bought a Hannah checker and tested again, maxed out with .90 normal dilution, returned a .8 at 50% dilution (so 1.6ish).

Nitrates at 50.

Started some gfo and did an extra wc, and 5 days later still at .80 on the checker.

Planning another wc this weekend and maybe some lanthanum chloride, just don't want to go too fast.

Elegance looking a little better but not much, gonis the same.

I'll get back under .5 and settle down maybe get to .25 if I can in time.
 
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ScottB

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Thats good information my friend thank you! So until then im dosing 2ml every morning just to make sure there is enough free in the tank for my coral. I did get info that i need more then 12 fish to help with this situation but again my bio load is dependent on feeding
Agree that plan. Should have mentioned that additional (beautiful) bioload made it easy to stop dosing. Fish poop is so much more stable and yummy for the reef. Test regularly. Document. Then dial export with skimmer, refugium, Wcs. Simple things. Linear things.

Later it is fun (if you have the time and attention) to play with carbon dosing and LC if needed. Just don't pull levers if you are not able to test results of those levers.
 

ScottB

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Currently my tank is at .8, very little algae though and some corals un happy but not overly so.

I was around .25 to .5 and everything seemed great for several months so I stopped checking. Oops.

Recently had my elegance start shrinking up (no other signs of ecs though, thank God) and my gonis not opening all the way. Otherwise everything seems happy, and not much algae in my tank. Tested and phosphate was 1.0+ on my red sea test. Wasn't satisfied with red sea so bought a Hannah checker and tested again, maxed out with .90 normal dilution, returned a .8 at 50% dilution (so 1.6ish).

Nitrates at 50.

Started some gfo and did an extra wc, and 5 days later still at .80 on the checker.

Planning another wc this weekend and maybe some lanthanum chloride, just don't want to go too fast.

Elegance looking a little better but not much, gonis the same.

I'll get back under .5 and settle down maybe get to .25 if I can in time.
Can't help you with gonis. Tried four times. They all doubled in size in 6 months then died. No changes. My LFS calls them renta-corals.

A bit racy there on PO4. That Hanna cuvette must have been so BLUE. You have room for LC at recommended dose levels. Easier to dial than GFO. Repeat weekly at recommended levels then go go super slow when you get to .2.

My number is .1 but you need to go super slow given current values. Trust only Hanna with spotless cuvettes and nitrile gloves.

You got here slowly. Get to .1 slowly.
 

NanJ

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I am with @Quietman and @Luciferene both.

New systems I keep managed a bit lower like .05 to .1

Once the system is mature 2-3 years, I prefer .1 ish. When it creeps toward .2 or so, I knock it back with lanthanum chloride. I find it much easier to dial & control than GFO.

Hanna is really the only reliable measuring tool. But you have to keep the cuvettes absolutely spotless.
How do you keep your cuvettes spotless? After draining the completed test I rinse the cuvette and cap 3 times with RODI water, then tap to try to get the excess water out, dry the outside, then leave on the counter to air dry. The cuvette has a film on the inside that I have tried removing with vinegar which did not help.
Do you have any other advice?
 

jl002837

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My main tank on my system is 360 gallons with
A 160 gallon sump/chemical tank and a 125 tank for a different look. Couple of large filters 30 pulse gallons, 1 large uv and a gfo filter system.
After 12+ years with several types of algae out breaks how do you know what your phosphate level is when you currently have algae in your system.
Will the algae give you a false reading on your test.
 

jason7570

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My phosphates were embarrassingly high. Took out my mangroves from my refugium and stirred up the sandbed. Whatever was in there released phosphates like crazy. Killed 3k worth of mushrooms and torches, all my other stuff ( even acros) looked amazing. When you wake up and see 3 gold torch colonies and your bounce shrooms melting definitely isn’t fun.

41A8B657-7492-41DB-AC3F-D564E137C7FB.jpeg
 

Timfish

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1. Do you worry about the phosphate levels in your reef tank?

Not exactly, I'm concerned about the different forms of phosphorus in my tank, particualate organic and dissolved organic a well the the dissolved inorganic form we generically refer to as PO4. Unfortunately our tests don't let us quantify particulate or dissolved organic so monitoring PO4 is the best we can do for now.

2. What is your target level of phosphates in your tank?

No particular number but generally a range above .03 mg/l and below .5 mg/l. The .03 mg/l is from research done at Southampton University in England showing that level as a minimum threshold to reduce the risk of phosphate deficiency in corals and the .5 mg/l from research with Acropora muricata showing increased growth but also reduced skeleton density. An alternate high number I sometimes give is .2 mg/l, which corals may be exposed to on reefs due to upwelling.

FWIW, a couple decades ago I realized there wasn't a link between high PO4 and nuisance algae. When I got active on the forums and saw recommendations in hte few parts per billion I was curious to see what the research by scientists showed since some of the claims on the forums was so contradictory to my experiences. For those interested here's some links I've collected over the years:

An Experimental Mesocosm for Longterm Studies of Reef Corals

Phosphate Deficiency:
Nutrient enrichment can increase the susceptibility of reef corals to bleaching:

Ultrastructural Biomarkers in Symbiotic Algae Reflect the Availability of Dissolved Inorganic Nutrients and Particulate Food to the Reef Coral Holobiont:

Phosphate deficiency promotes coral bleaching and is reflected by the ultrastructure of symbiotic dinoflagellates

Effects of phosphate on growth and skeletal density in the scleractinian coral Acropora muricata: A controlled experimental approach

High phosphate uptake requirements of the scleractinian coral Stylophora pistillata

Phosphorus metabolism of reef organisms with algal symbionts


Sponge symbionts and the marine P cycle

Phosphorus sequestration in the form of polyphosphate by microbial symbionts in marine sponges


Here's figure 3 from the above paper "Phosphorus metabolism of reef organisms with algal symbionts"
DIP DOP POP.jpg
 
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cheykaser

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My Reefer 250 was looking horrible after doing well for the first few months. I was getting white slime every were, corals bleaching and no polyps. My green slimmer looked like a white stick. No3 zero and PO4 Zero. Pulled all the Refug algae, turned off skimmer for a month, overfed my 7 fish like crazy, still haven't done a water charge in 7 weeks, and dosed NeoPhos until 0.10. Nitrates still zero but the tank gas never looked better!
 

fuelman

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How do you keep your cuvettes spotless? After draining the completed test I rinse the cuvette and cap 3 times with RODI water, then tap to try to get the excess water out, dry the outside, then leave on the counter to air dry. The cuvette has a film on the inside that I have tried removing with vinegar which did not help.
Do you have any other advice?
Keep rinsing it the same way but then fill it with rodi & store it full till the next use, that will stop the film build up. You will probably need some curvette cleaner to remove the film & get back to clean before that will work though.
 

AVVITT

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Worry doesn't help. My levels are higher than most, but everything is happy so if it's not broke, why fix it?

I believe I'm at .9 or 1.3 between there
I'm starting to realise that! I've spent so much time and worry chasing numbers which have been up and down all over the place and yet nothing in my tank has changed. All corals and fish seem happy so I've been stressing over nothing!
 

ScottB

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How do you keep your cuvettes spotless? After draining the completed test I rinse the cuvette and cap 3 times with RODI water, then tap to try to get the excess water out, dry the outside, then leave on the counter to air dry. The cuvette has a film on the inside that I have tried removing with vinegar which did not help.
Do you have any other advice?
That is a pretty good protocol. I actually store my cuvettes full of RODI. I also wear nitrile gloves when handling to avoid skin oil smudges.

As to the film inside, yeah I've had that before. I probably soaked in citric acid a few times over the years. I've also replaced my cuvettes a few times although they are not always readily available.
 

Mashbox

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Yes, after having a dino outbreak a few months ago I try to keep my nitrates at 5 and phosphates above .04.
Same reason I started paying attention closely to my Nit/Phos ratio. Dinos are a ***** to get rid of! Took me almost a month of dosing Nitrates/Phosphates to see an improvement. But, I finally beat it.
 

Belgian Anthias

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Yes, after having a dino outbreak a few months ago I try to keep my nitrates at 5 and phosphates above .04.
You will have a Nitrate:phosphate ratio in weight of 100/1. This means if for some reason growth increases drasticcaly ( increasing temp, high ammonia availability) nitrogen may support high growth rates until the organism grows dead due to phosphorus starvation, bleaching corals. Symbiodinium are dino's.
I try to keep the nutrient reserve below 10/1 because I like nitrogen to become the growth limiting factor.

Flagellates have the predisposition to predominate in a phosphate-poor environment. The strategy is to obtain organic phosphorus through the consumption of bacteria bacterivory. Since some bacteria can contain relatively high phosphorus reserves (PAO), the algal flagellates can proliferate in an environment where other competing algae and non-heterotrophic congeners find it difficult to meet their phosphorus needs. REF: MB CMF De Haes 2019
 

ReefGeezer

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How do you keep your cuvettes spotless? After draining the completed test I rinse the cuvette and cap 3 times with RODI water, then tap to try to get the excess water out, dry the outside, then leave on the counter to air dry. The cuvette has a film on the inside that I have tried removing with vinegar which did not help.
Do you have any other advice?
After rinsing a few times, I leave RODI water in mine. They still eventually need to be replaced. BRS has them for a couple bucks. When in doubt, replace.
 

arussellnsg

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I'm starting to realise that! I've spent so much time and worry chasing numbers which have been up and down all over the place and yet nothing in my tank has changed. All corals and fish seem happy so I've been stressing over nothing!
I'm no pro, but yes, it's not harmed anything for me, so I'm just carrying on... happy reefing
 

glb

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Mine are usually between 0.04-0.08, sometimes higher. I have a softie/LPS tank and the LPS do much better with some PO4 in the water. I don’t run GFO anymore because when the PO4 bottoms out, there’s all sorts of problems.
 
BRS

Do you keep "Reef Safe with Caution" fish?

  • YES (tell us what in the thread)

    Votes: 222 62.9%
  • NO

    Votes: 121 34.3%
  • Other (please explain)

    Votes: 10 2.8%
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