Selenium harmful?

[Big E]

I haven't seen anyone ever mention Selenium as being detrimental.

My ICP came back at 6.663 ug/l and .49 is ideal value

Anyone have any experience or links to it being a problem?

I know it's high due to my homemade food which I added salmon & sardines about 1.5 years ago.

This per Fauna---

Selenium - Fauna Marin

www.faunamarin.de

 

[Randy Holmes-Farley Verified Community Expert]

Like some other trace elements, selenium can come in many forms that will have different properties. That said, I do not know the toxic threshold of any of them offhand, even if you knew what form yours was.

Unless there’s an apparent tank problem, I probably would not worry about it.

Oceamo has this summary of selenium.

Selenium | Oceamo

Useful information about the element selenium in aquarium water.

en.oceamo.com

Any additional thoughts, @Christoph ?

 

[Christoph]

Hello!
Have you been dosing selenium? Otherwise its hard to explain how such a high level was reached.
We have seen negative effects from overdosing selenium, id recommend to lower it. Do you observe issues in your tank, especially with SPS?

GFO works well to bind Selenium, if your phophate level "allows" it. Id recommend increased trace dosing (apart from selenium) when you apply GFO, since it acts as a sink for almost all transition metal trace elements.
All the best,
Christoph

 

[Big E]

Hello!
Have you been dosing selenium? Otherwise its hard to explain how such a high level was reached.
We have seen negative effects from overdosing selenium, id recommend to lower it. Do you observe issues in your tank, especially with SPS?

GFO works well to bind Selenium, if your phophate level "allows" it. Id recommend increased trace dosing (apart from selenium) when you apply GFO, since it acts as a sink for almost all transition metal trace elements.
All the best,
Christoph

Yes, over months I have lost some colonies of SPS. Millepora have been most affected........it's slow over months. Low polyp extension then paleness & loss of zoo. Some corals haven't been affected at all.

I suspect it's due to my home made frozen food..........some of the ingredients are higher in Selenium vs of how I used to make it.

I added sardines and salmon to try to add more omega 3 for the fish.

Selenium levels-- per 3 oz.-- these are the highest in my mix

Salmon-36.5 ug
Shrimp- 49.5 ug
Sardines- 58.8 ug

I'm at .07 P04 not ideal to add GFO, but as you say I can use it for a short period of time and add trace elements.

My approach was to reduce by water changes and substitute foods with lower levels of Selenium

 

[Randy Holmes-Farley Verified Community Expert]

Thanks Christoph.

Do you think that organic forms of selenium bind to GFO, or do you think they are not the primary component, having been metabolized to inorganic forms that bind?

 

[Christoph]

Hi Randy,

id expect selenite and selenate being the predominant form (which is also reported for natural seawater). Low selenium levels and GFO usage correlate strongly in our result database, so that supports the hypothesis (since i would not expect organics to bind strongly to GFO).

All the best,
Christoph

 

[Randy Holmes-Farley Verified Community Expert]

Thanks, Christoph. :)

 

[Curiousbranching]

Yes, over months I have lost some colonies of SPS. Millepora have been most affected........it's slow over months. Low polyp extension then paleness & loss of zoo. Some corals haven't been affected at all.

I suspect it's due to my home made frozen food..........some of the ingredients are higher in Selenium vs of how I used to make it.

I added sardines and salmon to try to add more omega 3 for the fish.

Selenium levels-- per 3 oz.-- these are the highest in my mix

Salmon-36.5 ug
Shrimp- 49.5 ug
Sardines- 58.8 ug

I'm at .07 P04 not ideal to add GFO, but as you say I can use it for a short period of time and add trace elements.

My approach was to reduce by water changes and substitute foods with lower levels of Selenium

It's weird because I also use salmon as the main ingredient in my diy fish food but from my icp results my selenium always comes back with 0 ppb results

 

[Big E]

Salmon is the least amount of the Selenium levels compared to shrimp & sardines..................this may not even be the cause, but I'm going to try to reduce what's in my mix and see if the levels drop.

 

[Z Burn's Reefing]

Update? @Big E did you get your levels down and if so, how? Thanks!

 

[Big E]

I haven't sent out a new MS test to see. I stopped feeding as much of high selenium food & I'm assuming it's lowering per water changes.

There was also levels of aluminum and tin that were high which I didn't notice as the ATI test didn't flag them as too high. Chris Woods pointed them out to me.

Aluminum- 8.056 ugl/l
Tin- 2.808 ugl/l

I'm guessing that was coming from two large ceramic floor tiles I had in my system. I removed them about 10 days ago.

I had a few zoas melt but other than that everything else never showed any signs of stress.
Hammers, Torches, yuma & rics, favias, pipe organ. nepthea, weeping willow, ect.

I'll send out another test in about 30 days.

 

[Randy Holmes-Farley Verified Community Expert]

FWIW, I don’t think those levels of tin and aluminum are high enough to be a clear issue, though with tin the chemical firm will impact the tox.