Did adding Xenia reduce PO4 to Zero?

[Super Fly]

Tank PO4 levels were being maintained between 0.10 to 0.04 through regular GFO use (replaced every 2 weeks) and skimming 24/7. In fact I obtained a bigger skimmer believing current unit was too small.
In Feb, I added several heads of Pulsing Xenia (isolated on a rock island). Xenia is thriving, rapidly growing to appx 4-5x original size. Strangely this past weekend when I tested tank water, my PO4 was zero even though it should've been higher since GFO was due for replacement and I haven't done WC in a month. After 24 hrs of no GFO or skimmer, heavy feeding with nori, PO4 increased to 0.04.
I've kept GFO off while running skimmer 12hrs/day for now however just curious how/what caused zero PO4 when tank history tells me it shouldn't be. Thx

 

[Spare time]

I wouldn't think it could lower it that much. Also keep in mind it will eventually detach and leave the island it is on. I've seen tanks flooded with xenia and with no noticeable effect on phosphate (or at least it wasn't low)

 

[Super Fly]

I wouldn't think it could lower it that much. Also keep in mind it will eventually detach and leave the island it is on. I've seen tanks flooded with xenia and with no noticeable effect on phosphate (or at least it wasn't low)

That was the exact reason I had avoided xenia for years but I love their movement and look so couldn;t resist. A local reefer from whom I've been acquiring corals (I completely trust him) says this xenia species does not/has not dropped in his tank and likewise so far so good in my tank also.
Re. PO4 & Xenia, there are threads that discuss xenia as an effective PO4 reducer by growing in refugium.

 

[Spare time]

I guess it all depends on how much waste you have entering your tank in a day vs how much the xenia is removing. Do you have many fish?

 

[Uncle99]

Quite possible accounts for the reduction, or at least is contributing to it.
Xenia are experts at sucking up those nutrients.
Same with GSP.

 

[Super Fly]

I guess it all depends on how much waste you have entering your tank in a day vs how much the xenia is removing. Do you have many fish?

not much, 93 cube w one spot foxface, lyretail anthia, pair of clowns, tomini tang n firefish.

 

[Super Fly]

Quite possible accounts for the reduction, or at least is contributing to it.
Xenia are experts at sucking up those nutrients.
Same with GSP.

oh u may have hit the nail right on the head! Same time when Xenia was added I also added a large rock full of GSP. That explains a lot, thanks!

 

[Super Fly]

U can see the size of GSP rock on lower right front corner w xenia next to it. Both are rapidly growing, pix after 1 month in tank

 

[Timfish]

Corals love phosphate so depending on how heavily you feed and how fast Xenia is growing it's possible it could drop your levels. In fact in his book "Algae, a Problem Solving Guide" Julian Sprung makes the point fast growing corals can be used for just this purpose.

Also cryptic sponges can store excess phosphorus as crystals in thier tissue and biofilms can be a phosphate sink as well.

(Xenia can be troublesome but here's a technique I developed to control it.