Fish lowering phosphates?

[Reefkeepers Archive]

@Randy Holmes-Farley and every other reef chem experts, I've noticed some weird pattern with the addition of a fish to low phosphates in my tank, the system is about a year old, 120 gallons,n LPS dominant and no water change and po4 usually sits around .06, but I've noticed during both times I've added a medium sized fish the po4 seems to go down!?! I checked today and it was at 0.03, which is the same number it was at last time a fish was added... I don't frequently check nitrates but other than the fish the only things that change were me replacing the GHA in the refeugium (as it was decaying during a recent power outage) and me feeding the corals less at night to make room for feeding the fish during the day. I don't know if the fish or the refeugium is what is contributing to these numbers, any ideas?

 

[Randy Holmes-Farley Verified Community Expert]

I do not believe fish take up any phosphate from the water. A fed fish is a net source of N and P to the water.

are you feeding differently?

 

[EeyoreIsMySpiritAnimal]

feeding the corals less at night to make room for feeding the fish during the day.

To Randy's question, what specific changes did you make?

 

[Garf]

feeding the corals less at night

What are you feeding the corals? Something high in phosphate?

 

[Reefkeepers Archive]

To Randy's question, what specific changes did you make?

What are you feeding the corals? Something high in phosphate?

I do not believe fish take up any phosphate from the water. A fed fish is a net source of N and P to the water.

are you feeding differently?

I feed mysis shrimp to the corals, now done less than previously, nothing too high in po4, I replaced the dead gha with living gha from my display and added a few jars of algaebarn copepods. That's about all I've changed

 

[EeyoreIsMySpiritAnimal]

I feed mysis shrimp to the corals, now done less than previously, nothing too high in po4, I replaced the dead gha with living gha from my display and added a few jars of algaebarn copepods. That's about all I've changed

I love that you embrace the inevitable and use gha in your fuge!
You may never figure out the "why". But going forward, test things regularly to make sure phos doesn't bottom out...

Also, it's possible the dying/dead gha raised the nutrients

 

[Reefkeepers Archive]

I love that you embrace the inevitable and use gha in your fuge!
You may never figure out the "why". But going forward, test things regularly to make sure phos doesn't bottom out...

Also, it's possible the dying/dead gha raised the nutrients

Well now I have an excuse to feed a little more ;)

 

[Garf]

Well now I have an excuse to feed a little more ;)

Back to feeding the corals then :)