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Lowering phosphates


KimP

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I want to lower my phosphates using gfo in my mixed reef. I know to start slow, but what does that really mean? Say I tested every day, what might be a safe ppm to lower it each day or week or...?

 

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The only recommended number I remember ever seeing is .5 ppm per day.  That's quite a lot considering many people consider .02-.04 ppm to be a good range to be in.  For me, on a 150 I'd start with about a cup of GFO in your reactor, make sure it is slowly tumbling, and monitor.  You should see some measure of a reduction in PO4 within 24-36 hours. 

Don't forget GFO is just a bandaid; need to ID what's pushing your PO4 levels up and make a change.  🙂

Edited by Sierra Bravo
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The only recommended number I remember ever seeing is .5 ppm per day.  That's quite a lot considering many people consider .02-.04 ppm to be a good range to be in.  For me, on a 150 I'd start with about a cup of GFO in your reactor, make sure it is slowly tumbling, and monitor.  You should see some measure of a reduction in PO4 within 24-36 hours. 
Don't forget GFO is just a bandaid; need to ID what's pushing your PO4 levels up and make a change.  [emoji846]
Okay, thanks! I'll watch for a change within a few days. Hopefully I can bring it down nice and slow. As far as what's the real cause I'll have to do some thinking. It's been at it's current level for as long as I can remember. I'll need to look back at any notes I left over the years. It has been getting a 20-25 gal water change every week for maybe 6 months now and I run chemipure blue. Neither the water changes nor the media has lowered the phos any.

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test your change water for phosphates every once in awhile... you'd be surprised how many times the "new" water is actually higher than the "old"
Great idea. I haven't ever checked that.

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Well, in nature upwelling can expose corals to levels as high as ~2.0 mg/l, and upwelling can change or stop pretty quickly so corals should be able to handle what we would consider fairly large changes.   Dunn, et al reviews some of the research looking at inorganic phosphates, while there are clearly species-specific responses, PO4 levels much higher than is often suggested by "gurus" does not appear to affect skeletal density and may increase calcification rates.   In light of the research done by Southampton University* showing the problems corals have with PO4 deficiency at the above suggested levels I would not let PO4 drop below .1 mg/l and it's not something that needs to be done quickly.  

 

*  Here's the links for Rosset, Wiedenman and De Angelo's research at Southampton University

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 reef coral holobiont

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

 

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Before I upgraded, I ALWAYS had high phosphates in my 55. Ty tested my water once and said that was the first time he’d ever seen the reactant turn the water sample blue. [emoji15]. It was suggested that bc they were so high for so long, that my rocks just kept leaching the PO4 back out. So, even when I’d do a water change, the PO4 never went down bc it was in the live rock. Don’t know if it was true, but it made sense. I used new rock in my upgrade, and have had much better levels


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17 minutes ago, Christyef said:

Before I upgraded, I ALWAYS had high phosphates in my 55. Ty tested my water once and said that was the first time he’d ever seen the reactant turn the water sample blue. emoji15.png. It was suggested that bc they were so high for so long, that my rocks just kept leaching the PO4 back out. So, even when I’d do a water change, the PO4 never went down bc it was in the live rock. Don’t know if it was true, but it made sense. I used new rock in my upgrade, and have had much better levels


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Interesting. I've heard of the rock leaching phosphates. I'm still adding gfo for now, hoping to see results with that. My make up water tested 0.

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