Where is my phosphates coming from?

[QuinnLee512]

I've had my RSR 350 up for a year now. Everything had been fine until a few weeks ago. I started losing corals and my phosphates have been all over the place. This morning it was reading .17. This afternoon it's at .35. I only did one small feeding of benepellets which should have minimal nutrients. I've been using rowaphos, phosphate-e, chaeto in fuge. My rodi reads .04 which isn't an issue. Nothing is working. Where is all this phosphate coming from? Leaching from rocks?

 

[Dan_P]

I've had my RSR 350 up for a year now. Everything had been fine until a few weeks ago. I started losing corals and my phosphates have been all over the place. This morning it was reading .17. This afternoon it's at .35. I only did one small feeding of benepellets which should have minimal nutrients. I've been using rowaphos, phosphate-e, chaeto in fuge. My rodi reads .04 which isn't an issue. Nothing is working. Where is all this phosphate coming from? Leaching from rocks?

After a year, we have to stop blaming the aragonite :-) We should also separate the losing coral and erratic phosphate reading observations. It seems you are using three methods to manage phosphates. That’s where I would look first for the source of variability. Could testing be another source of variability?

 

[Miami Reef]

Phosphate shouldn’t be causing coral issues, even at the levels you reported.

Sometimes the test result can vary throughout the day based on particles, feedings, or algae scraping.

 

[VintageReefer]

My phosphate jumped from .35 to 1.04, and I lowered over the course of a week and just got it down to .7

Haven’t lost one coral nor had any sign of stress

.17 and .35 aren’t bad. I would look for other possibilities for coral losses. I doubt it’s the phosphate levels

If your asking how it raised by itself, could be from feeding or fish / coral biological process causing a increase, and then your media should bring it back down.

Does it increase and stay? Does it continue to increase until you intervene? Does it increase then decline back down by the next day? Look for a pattern

If the rocks are bound up, and the media is removing from the water column, then the level will go down temporarily, the rock will unbind phosphate, and then it will go back up to whatever equilibrium the tank is used to. This can happen for months before a new, lower equilibrium is created

 

[QuinnLee512]

I'm using a hanna checker so I doubt the readings are wrong. I also have a hard time keeping my nitrates from bottoming out. Is that what's killing my corals? I started dosing Neo-Nitro to add nitrates.

 

[VintageReefer]

I'm using a hanna checker so I doubt the readings are wrong. I also have a hard time keeping my nitrates from bottoming out. Is that what's killing my corals? I started dosing Neo-Nitro to add nitrates.

Zero nitrates will do it

 

[QuinnLee512]

Thanks. I guess I've been worrying about the wrong nutrient. :⁠-⁠(

 

[Randy Holmes-Farley Verified Community Expert]

Thanks. I guess I've been worrying about the wrong nutrient. :⁠-⁠(

This has more discussion of that topic:

https://www.reef2reef.com/ams/randy’s-thoughts-on-nutrient-target-ranges.1087/

 

[QuinnLee512]

So my nitrate is at 9.2 and phosphates at .27 today. Should I be concerned about the high phosphates? I know it's below Randy's .3 range. I just don't have the slightest clue where it's coming from. Benepellets aren't cheap but I got it for the purpose of not adding a lot of nutrients during feeding so I'm totally baffled.

 

[Randy Holmes-Farley Verified Community Expert]

So my nitrate is at 9.2 and phosphates at .27 today. Should I be concerned about the high phosphates? I know it's below Randy's .3 range. I just don't have the slightest clue where it's coming from. Benepellets aren't cheap but I got it for the purpose of not adding a lot of nutrients during feeding so I'm totally baffled.

All foods contain phosphate. The issue is just matching addition to consumption/export.