Trying to solve high phosphates

[Dom]

So... here's the rub...

Typically, my phosphate levels test around .25, which I thought was a good number.

Then I read "Phosphate and the Reef Aquarium" by Randy Jones-Farley. In the article,
it states: " target a phosphate concentration of 0.02 ppm phosphate, or less ". Based on that statement, it sounds like my phosphates are terribly high.

I have been trying to solve why some frags in my tank have not growing. My Zoa frag took off for a while and started to cover a piece of live rock. But now the growth has stopped. My other frags, while surviving, have not grown at all.

If I understand correctly, elevated phosphates inhibit calcification. Can a calcium level of .25 prevent corals in the uptake of calcium and prevent their growth?

 

[Randy Holmes-Farley Verified Community Expert]

I may be hurting growth. So might other things.
Can you post the other things you've tested, such as alkalinity and nitrate?

 

[Dom]

I may be hurting growth. So might other things.
Can you post the other things you've tested, such as alkalinity and nitrate?

The following test results are from 9/1/16:

SG: 35
pH: 8.15
Amonia: 0
Nitrate: 0
Nitrite: 0
Phosphate: .25
meq/L: 2.5
dKH: 8.1

Regardless of whether phosphates are hurting growth, I'd still like to resolve the .25 on phosphates. My fuge has chato and some other algae indigenous to the area. It has been wonderful in terms of getting my nitrates down to zero, but not phosphates. Is there some other macro algae that would use the phosphates present?

 

[rock_lobster]

what test kit? have you checked it with a standard solution for accuracy? Also you could use some phosphate absorbing media in the meantime. Its is most likely leaching from your rocks and sand so it cant hurt.

 

[Macdaddynick1]

Biggest problem i personally ran into , is high phosphates and low nitrates. especially with zoas . so you might be in a similar situation.

 

[Randy Holmes-Farley Verified Community Expert]

The nitrate being too low might be a worse problem for corals than the phosphate being high.

The phosphate can be reduced in many ways, including GFO.

Either 2.5 meq/L or 8.1 dKH are fine for alkalinity, but those are different and like saying the temp is 32 deg F and 5 deg C. They do not align. 2.5 meq/L = 7.0 dKH

 

[Dom]

what test kit? have you checked it with a standard solution for accuracy? Also you could use some phosphate absorbing media in the meantime. Its is most likely leaching from your rocks and sand so it cant hurt.

All test equipment has been verified/calibrated for accuracy.

 

[Dom]

The nitrate being too low might be a worse problem for corals than the phosphate being high.

I never realized that nitrates could be too low. But I don't think that is the issue as this is something that goes on, even when my nitrates are around 10.

Perhaps a phosphate removal pad...

 

[Randy Holmes-Farley Verified Community Expert]

A pad can work, but may be more expensive than granular GFO.

 

[Dom]

A pad can work, but may be more expensive than granular GFO.

Agreed. But the current sump is set up in a way that will readily accept a pad.

 

[beaslbob]

IME 1) the algae is the biggest sump for phosphates and more importantly 2) it took a few months in my system for phosphates to drop to unmeasurable levels after nitrates were unmeasurable.

Hopefully you phosphate test kit measures below .25ppm.
Some kits (especially ammonia kits) aren't very precise at low levels.

my .02

 

[beaslbob]

oh yea.

dosing nitrates (5-10ppm) will help lower phosphates.