How fast can GFO remove PO4?

[-Logzor]

So I've been conducting an experiment, dosing around 10-20oz of phyto a day on my aquarium. Things were going really well and the color on my Icefire and German Blue Polyp acros were looking amazingly. After a couple weeks into dosing I noticed one of my acros STN'ing. I decided to tell my PO4 with my Hanna meter, it was at 0.71! I've always measured 0.00 in my system. I suspect the fertilizer was not fully digested by the phyto in one of the bottle I dosed (I culture it myself).

Although I'm not 100% sure it was the PO4...at the same time my Dkh spike to 16.8. My dosing pump had been set a little high and I was doing small daily water changes, I'm guessing the salt mix was super-high in alkalinity.

Amazingly, even with that high of Dkh and PO4, some of my acros looked better than they ever have. I also noticed that most of my coraline algae growth stopped and began to flake off. I run a BB system so the bottom of the tank had been covered in coraline, but most of flaking off, although I had moved some frag plugs around a couple weeks ago over the coraline, when I moved those same frags the other day the coraline was totally intact and healthy looking, like it was protected. Strange.

So I had some GFO on hand, I added about 50mL into my system (I think this is about 1/4 cup) via BRS dual-reactor. In 24 hours my PO4 went from .71 to .42 in a 180g system. Pretty incredible.

My advice is to only run GFO when you have detectable P04. GFO strips the water so quickly it can lead to RTN issues or pale corals.

I also need to figure some way to know that the phyto is fully digested, any thoughts so I don't PO4 bomb my system again?

 

[Masgatigata]

I'm tagging along for this one. I'm currently running gfo again when my phosphates got out of hand. My phosphates are currently at 0, but I find that my sps do much better when my po4 are at about .02-.03. So, I'm currently running gfo, and feeding oyster fest in a daily basis to hopefully insure the color an growth of my sps. Hopefully this feeding will offset the o phosphate reading.

 

[Pappy]

So r u saying the gfo caused the RTN and not the 16.8 dkh? I run gfo 24/7 and dkh at 8-9 and ca at 440 and never an issue is why I ask.

 

[-Logzor]

So r u saying the gfo caused the RTN and not the 16.8 dkh? I run gfo 24/7 and dkh at 8-9 and ca at 440 and never an issue is why I ask.

No, sorry I probably didn't explain it that well. My post was kinda random. My point was that a very small amount of GFO can rapidly remove a lot of PO4. In my case the high PO4 / High DKH caused the RTN. Luckily it was only on one coral that I didn't even really like that much. LOL

I think many people are able to strike a good balance when running GFO 24/7 but in every RTN/Pale Coral thread I read GFO is being used. I think in a lot of cases this is due to PO4 being way too low. All organisms need some PO4 to survive.

In the past I never ran GFO because every time I did my corals would turn pale in a week. This is probably due to the fact that my system was already extremely clean.

So I'm just trying to show that it's easy to over-do GFO if you already have a clean tank.

Pappy I'm guessing in your case you strike a good balance between PO4 in and and PO4 out (via GFO). That's what I hope to achieve by using the right amount.

 

[-Logzor]

I'm tagging along for this one. I'm currently running gfo again when my phosphates got out of hand. My phosphates are currently at 0, but I find that my sps do much better when my po4 are at about .02-.03. So, I'm currently running gfo, and feeding oyster fest in a daily basis to hopefully insure the color an growth of my sps. Hopefully this feeding will offset the o phosphate reading.

I think you've nailed it, hitting that just above 0 is the ideal level.