School me on Phosphates

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Sticker shock

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So I‘ve been running my reef for a year now. There was a two month period or so where I had detectable phosphate, that was during the second and third month or so of having my tank. Ever since then, my tank has been running at 0 phosphates and nitrates at between 5 - 25 depending upon when my last water change was. I don’t do anything special to remove phosphate except run a skimmer (which I empty maybe biweekly) Other than that, I just have rock and a canister for filtration. I feed fairly heavily with white worms and reef frenzy (3 times a day) for the 4 fish that I have. I also feed reef roids to my corals weekly. Why would my levels stay so low? Are there just no phosphates in these foods? Fish are happy and healthy, so I really don’t want to change feeding schedule. Should I dose phosphate? Looks like a small case of Dino may be brewing...already dealt with this once and really don’t want to again.
 

PatW

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Any food will have phosphates. They are an essential part of many critical biomolecules. So you are adding phosphates.

First off, what test are you using? The hobby grade tests are mostly far too insensitive to be of much use for phosphate. The only test that is sensitive enough is the Hanna ULR phosphate test or the Hanna ULR phosphorous test (which is even more sensitive according to my reading).

The thing is that the source of your phosphates in your tank comes in food. The food will be converted to fish poo and some of it in inorganic phosphates which the tests can detect. But if your skimmer is really efficient. It might be removing nearly all of the fish poo. So no phosphate from that.

Now some of the food will wind up as inorganic phosphate but there will be some bacteria in the water and the skimmer will get them. Also the algae will take up some phosphate. And corals will use the fish poo and inorganic phosphates.

In facts, a number of SPS producers run very low phosphate numbers and feed the corals the phosphates they need by really feeding the fish and thus producing lots of fish poo that the corals can use and gets removed by the skimmer.
 
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Sticker shock

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Currently I’m using the Salifert test kit, but have already ordered the ULR phophate checker from Hanna. I feed my fish enough that I’m sort of uncomfortable feeding more. So I guess for now I should get more fish or turn down my skimmer even more? Also I have no noticeable algae...I’m sure there is some as my clean up crew is alive and I do have to clean off my glass. But there really is no macro algae to speak of.
 

piranhaman00

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Salifert test kit cannot determine PO4 levels accurately. Not a jab at Salifert, I love and use all their kits, but the color change is too small. Wait until the hanna comes to make an adjustment.
 
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infinite0180

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I struggle to get detectable phosphates. I use the Hanna ULR. I recently moved to a new tank but kept the same rock. I turned my new lighting up too high with no phosphates and bleached all my sps. Some of them where over a year old and turning into nice colonies. Ive never had a problem with nitrates and tend to keep them above 10 but less than 20. After this mini crash im restocking the tank but before i do i decided to dose po4 until it stabilizes above 0.05. Well after about two weeks of testing and dosing reletively large amounts of trisodium phosphate im finally stabilizing at 0.05. Im really going to try and maintain that level from here on out, dosing if necessary. Heres a good resource to watch that im following.
 

rob safron

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I have always rode the 0 phosphate and near 0 nitrate also regardless of feeding. I stated dosing AcroPower 3 mls every day and phosphates are hanging in the 0.03-0.04 range. Corals are doing much better. If your polyps are tight and corals look rough I would believe the Salifert test kit.
 
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Sticker shock

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SPS are doing ok, but very slow growing. Polyp extension is good, but I'm pretty new to SPS at this point. Zoa's I have an awful time with. More than once I've added a frag that closes up and just melts away. Not sure if it's phosphates or something else, but I haven't been able to identify any pests.
 
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Ordered my supplement this morning. Is .03 a safe target to shoot for?

I also stopped my skimmer this morning, I’m thinking I may run it on a reduced schedule to see if that helps. Bad idea, or worth a try?

It’ll be a few days until I get my hanna checker and supplement, so I’m hoping this might slow the dinos before they become an issue. I have fresh saltwater ready to go, but unsure if that is a bad idea or not. I’ve read water changes can super charge dinos.
 
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MabuyaQ

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Since you have quite a swing in nitrate from 5 upwards to 25, you can easily go 0.05 to 0.10 on phosphate.
My personal rule is phosphate = nitrates/100 with a maximum of 0.1 and a minimum of 0.02 (I use a Hanna phosphorous checker). So in your case 5/100= 0.05 (which is above 0.02) to 25/100=0.25 ( which is above 0.10 so that becomes the max.). My only rule on nitrate is, don't let it drop under 2ppm for to long. There is a rule on a maximum (for nitrates) but that is mainly there because I don't want to grow to much algae.
 
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infinite0180

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Yea id go higher than 0.03. Also dont be surprised if you dose in the morning and test later that day and see no increase. My tank was sucking up the po4 every dose in a matter of hours for the first few weeks...
 

MERKEY

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Did you start your tank with live wet or dry rock?

Just a thought...our phosphates starting leaching out of our rocks and sand around the 1 year mark.

I'm not saying this is happening to you but in would get that Hannah kit before I started dosing phos.

If it is that low kuddos to you and definitely dose phos to get .03 ;)
 

MERKEY

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Started with pretty much all dry rock. I just used a couple small pieces of live rock to seed the tank. I guess my rock has been absorbing all the phosphate? I really doubt my coral would be using it at this point since all I have is small frags for the most part.
It could be but just check with the Hannah to be sure ;)
 

Randy Holmes-Farley

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Just a thought...our phosphates starting leaching out of our rocks and sand around the 1 year mark.

What makes you say that? I do not really see a reason that rocks start releasing phosphate a year after a tank is set up.

How do you know that isn't when the rocks stopped absorbing phosphate because they were saturated relative to the phosphate in the tank?
 

MERKEY

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What makes you say that? I do not really see a reason that rocks start releasing phosphate a year after a tank is set up.

How do you know that isn't when the rocks stopped absorbing phosphate because they were saturated relative to the phosphate in the tank?
This was the case in my tank. My dry rock built up/bound the phosphate and then began releasing it. At least thats the conclusion this forum came to when I was having my issue.

Maybe that was not my issue at all but I didn't change feeding habits and removed phos with phosgaurd...this was over a couple month period.
Now phos holds steady but the conclusion I gathered from members here was the rocks and sand bound the phos.

If I miss understood what I was given as advice then I think there are more people on this forum than myself that think dry rock holds/binds phos.

And perhaps the rocks do stop absorbing but at a point when you start removing I believe they would start to release from the rocks as well.

This is a great theory and I wish it was brought up while I was removing the phos. It would have been interesting to try and track that somehow.
 
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Randy Holmes-Farley

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This was the case in my tank. My dry rock built up/bound the phosphate and then began releasing it. At least thats the conclusion this forum came to when I was having my issue.

Maybe that was not my issue at all but I didn't change feeding habits and removed phos with phosgaurd...this was over a couple month period.
Now phos holds steady but the conclusion I gathered from members here was the rocks and sand bound the phos.

If I miss understood what I was given as advice then I think there are more people on this forum than myself that think dry rock holds/binds phos.

And perhaps the rocks do stop absorbing but at a point when you start removing I believe they would start to release from the rocks as well.

This is a great theory and I wish it was brought up while I was removing the phos. It would have been interesting to try and track that somehow.

How can you distinguish "stopped binding it" from "then began releasing it."?

I do not think the latter happens , unless you are trying to drive down the water phosphate. It doesn't just come off one day. it is constantly going on and off in equilibrium with the free phosphate in the water.

Phosphate binding to calcium carbonate and other minerals is not really a "theory" in the sense of having any uncertainty. It is well studied and published science. :)
 

MERKEY

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How can you distinguish "stopped binding it" from "then began releasing it."?

I do not think the latter happens , unless you are trying to drive down the water phosphate. It doesn't just come off one day. it is constantly going on and off in equilibrium with the free phosphate in the water.

Phosphate binding to calcium carbonate and other minerals is not really a "theory" in the sense of having any uncertainty. It is well studied and published science. :)
Distinguishing would be the point.

To find a way to track that would be what I was referring to.
 
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