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: 267 56.4%
  • No I try to keep mine at zero

    Votes: 46 9.7%
  • I don't worry about phosphate levels

    Votes: 143 30.2%
  • Other (please explain)

    Votes: 17 3.6%

  • Total voters
    473

blackstallion

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After fighting cyano when I was NOT testing for Phosphates and Nitrates (which bottomed out at 0), I started dosing Brightwells NeoPhos and NeoNitro until I registered some level's, and then started overfeeding my fish to maintain the levels.

Tested on Hanna checker's, I've been trying to maintain Nitrate of 1-5ppm and Phosphates between 0.03-0.1ppm.
 

Dragonsreef

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For my sps dominant system i target 0.08 but anything from 0.03-0.12 seems to be fine. When it starts getting near 0.2 i notice significant color loss in the acros.

In my softie and lps system they are generally anywhere from 0.15-0.3 and i dont notice any significant difference. But i will see the health of the lps decline when it starts getting over 0.5
 

Marc2952

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I worry alot now that im going fallow lol have to constantly dose it just to keep it up and thats including me adding food to the tank daily and pellets 4 times a day.
 

danieyella

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I don't bother checking for them. Maybe if I had a problem I'd look into it.

I tried the whole stressing about them thing towards the beginning and caused more problems than I solved.
 

Jax15

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I don't really worry about P. Check once every 3 months or so, and if it's under 0.1 I'm happy. My tanks a few years old now, and I've realized that it'll self-regulate so long as I'm consistent with feeding.
 

Calm Blue Ocean

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As it often seems, yet another timely QotD! I'm in the midst of trying to wrap my head around this whole PO4 thing right now.

Tank is just about to hit the one year mark, started with dry rock.

Last fall I had everything bottom out and ended up with dinos. Dosed up my nitrates and phosphates as part of the battle and everything seemed good, right on target. But sometime around Feb or March something changed and I can't figure it out for the life of me. PO4 has been rising at an alarming rate. I see people panicking because their PO4 is 0.08 (and I'm not downplaying that, different tanks have different needs). First I hit 0.3. A month later it was 0.4. Then my Hanna was flashing 200 and I had to dilute my sample to get a reading. Then diluting by half wasn't enough! Ok, full on panic time! Regular weekly water changes didn't touch it. Yesterday I did a 30% water change (the biggest I'm equipped to do) and actually saw a reduction, thank goodness. Still over the max on the Hanna checker but we take progress where we can get it. I'll do another 30% next week.

My goal for PO4 is 0.1. After dinos I'm afraid to go any lower.

People ask if I've seen anything negative from my high PO4. My kneejerk answer is always no, things look generally good. No algae (I'm honestly worried my CUC might starve). But I've started going through pictures and I've realized something isn't right. I lost 3 corals that pretty much gradually melted away (two montis and a cyphastrea). Stony stuff doesn't grow. Soft tissue seems to grow like crazy. I prune my Kenya tree every week. But anything with a skeleton is in stasis although looking generally healthy.

I'm lowering my PO4 cautiously. I'll be interested to see if things with skeletal structures start to grow when I get things under control.
 

90's reefer

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In my 120 my target is .06 or less.
However .1 is fine in my system.
I run phosgaurd when it gets to .2.

Just checked as its been awhile and it was 92 or .28.
Running phosgaurd now until it gets to .06 then I am going to run a small amount continuously to keep it under .1.

I feed heavy at 8 cubes a day for the 14 fish.

I follow heavy in heavy out and need to check po4 more often.

When it gets above .2 my colors are affected, as in not as bright.
After I read this thread I did notice the colors were off, lol.

My no3 runs 5 or less most of the time.

I stopped carbon dosing about 3 weeks ago and that is probably why my po4 is up.

I am back to minimal, 5ml a day, of ez carbon and will stick with that.
I was using it to feed the corals and bacteria and not to control po4, although it probably did.
It did bring my no3 down from 10 though.


I have no algae issues to speak of.

If you feed heavy you can run low numbers combined with heavy export.

No3 and Po4 that we measure in our systems is what is left over from what our export system is not removing.
 

Qantos

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Yes!! I'm just coming out of an ugly battle with amphidinium dinos from a tank that was too clean (0.00 ppm phosphates). I feed my fish pretty heavily but was never able to get a measurement on the Hanna checker.

This went on for a couple months and then dinos exploded and killed several corals. The solution was dosing pure nitrates and phosphates from Brightwell along with MB7 and live phytoplankton daily to increase biodiversity.

My nitrates are pretty stable now but I'm still dosing a ton of phosphate every day to keep my concentration around 0.1 ppm.

Lesson learned the hard way... keep an eye on your nutrients and don't let them bottom out.
 

Rewd

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In my old tanks I never even tested for phosphate. After returning to the hobby after 15 years I try to keep it between 0.03 and 0.12 and usually run at 0.07.
Same here! I'm returning after a decade absence. My phosphate is 0.03 according to my Hanna checker. What are you doing to maintain 0.07 and keeping it in the range you stated?
 

jenniferreichardt

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As it often seems, yet another timely QotD! I'm in the midst of trying to wrap my head around this whole PO4 thing right now.

Tank is just about to hit the one year mark, started with dry rock.

Last fall I had everything bottom out and ended up with dinos. Dosed up my nitrates and phosphates as part of the battle and everything seemed good, right on target. But sometime around Feb or March something changed and I can't figure it out for the life of me. PO4 has been rising at an alarming rate. I see people panicking because their PO4 is 0.08 (and I'm not downplaying that, different tanks have different needs). First I hit 0.3. A month later it was 0.4. Then my Hanna was flashing 200 and I had to dilute my sample to get a reading. Then diluting by half wasn't enough! Ok, full on panic time! Regular weekly water changes didn't touch it. Yesterday I did a 30% water change (the biggest I'm equipped to do) and actually saw a reduction, thank goodness. Still over the max on the Hanna checker but we take progress where we can get it. I'll do another 30% next week.

My goal for PO4 is 0.1. After dinos I'm afraid to go any lower.

People ask if I've seen anything negative from my high PO4. My kneejerk answer is always no, things look generally good. No algae (I'm honestly worried my CUC might starve). But I've started going through pictures and I've realized something isn't right. I lost 3 corals that pretty much gradually melted away (two montis and a cyphastrea). Stony stuff doesn't grow. Soft tissue seems to grow like crazy. I prune my Kenya tree every week. But anything with a skeleton is in stasis although looking generally healthy.

I'm lowering my PO4 cautiously. I'll be interested to see if things with skeletal structures start to grow when I get things under control.
You are exactly where I am. Mine, however, stays around .3-.4.
 

David S

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I like to keep my PO4 below 0.10. Generally, in the .03 - .05 range.
I have found that levels above .10 - .20 and nuisance algae makes its appearance.
Funny that some people have said they like to keep their PO4 slightly elevated for their SPS. I know that at my low levels my LPS do great, while my Acros are just OK. I would think it would be the other way around.
 

ClownWrangler

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https://www.nature.com/articles/srep31768

As outlined in this study, the nitrogen/phosphate balance that zooxanthellae require to thrive is dependent on temperature. If the objective is to grow corals while minimizing GHA, perhaps there is more to this worth looking into. However I don't think algae should be a determining factor. That's what clean up crews are for.
 
Last edited:
BRS

WHAT WATER CHANGE "PERCENTAGE" MAKES IT WORTH DOING?

  • 5% - 10%

    Votes: 26 13.0%
  • 10% - 20%

    Votes: 106 53.0%
  • 20% - 30%

    Votes: 39 19.5%
  • 30% - 40%

    Votes: 6 3.0%
  • 40% - 50%

    Votes: 2 1.0%
  • 50% or more

    Votes: 0 0.0%
  • No water change is worth it

    Votes: 4 2.0%
  • Not sure

    Votes: 5 2.5%
  • Other (please explain in the thread)

    Votes: 12 6.0%
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