Activated carbon stripping trace elements

[Makara23]

My macro algae grows very fast and it's quite obvious after it consumes all of the trace elements it needs to grow. This is when it starts to deteriorate. When I dose small amounts of ChaetoGro, it perks up the next day.

I want to start using activated carbon to remove odor and possibly toxins from corals. But will carbon media also soak up the trace elements from ChaetoGro? Will it also remove organics that the filter feeding hitchhiker and corals eat?

Chemical composition of ChaetoGro:

• potassium (1.3%)
• boron (0.009%)
• carbon (0.005%)
• calcium (0.14%)
• chlorine (0.39%)
• iron (0.32%)
• magnesium (0.4%)
• manganese (0.0475%)
• molybdenum (0.004%)
• cobalt (0.0004%)
• nickel (??)
• sulfur (0.16%)
• zinc (0.002%)

 

[vlangel]

My macro algae grows very fast and it's quite obvious after it consumes all of the trace elements it needs to grow. This is when it starts to deteriorate. When I dose small amounts of ChaetoGro, it perks up the next day.

I want to start using activated carbon to remove odor and possibly toxins from corals. But will carbon media also soak up the trace elements from ChaetoGro? Will it also remove organics that the filter feeding hitchhiker and corals eat?

Chemical composition of ChaetoGro:

• potassium (1.3%)
• boron (0.009%)
• carbon (0.005%)
• calcium (0.14%)
• chlorine (0.39%)
• iron (0.32%)
• magnesium (0.4%)
• manganese (0.0475%)
• molybdenum (0.004%)
• cobalt (0.0004%)
• nickel (??)
• sulfur (0.16%)
• zinc (0.002%)

I am not strong in the chemistry aspect of aquaria, but I keep a lot of macroalgae in my display for both the ornamental appearance as well as the nutrient uptake. I also use about 3-4 Tbsp of carbon that I change out weekly along with filter floss. I dose Coral vite weekly to replenish trace elements and occasionally iron, and Flourish. I have not noticed that the macroalgae are impacted by the use of carbon.

 

[Randy Holmes-Farley Verified Community Expert]

Many trace elements bind organics and those organics will be impacted by a variety of Reefing practices such as GAC and skimming, but I do not think it’s a reason to avoid GAC, and the info brought to bear on this question from freshwater and wastewater tests of GAC are likely misleading for seawater where there is far more competition from binding sites on gac from all of the other ions. .

 

[taricha]

I think of it this way. If I look at what collects in my skimmer cup and ask what elements are in it?, I would conclude that many "good things" got skimmed out.
However, I'm going to run the skimmer anyway. Because there's much more undesirable stuff that I'd rather got removed. And I can accept or correct the lower levels of "good things" as a result of skimming.

I feel the same about GAC.

 

[DeputyDog95]

If you're continually low on certain trace elements per the ICP, and you're manually adding those trace elements, could carbon be a culprit?

 

[Randy Holmes-Farley Verified Community Expert]

If you're continually low on certain trace elements per the ICP, and you're manually adding those trace elements, could carbon be a culprit?

I doubt it is a big sink relative to organisms and other sinks, but I’ve never seen any useful data in that regard.

 

[DeputyDog95]

I doubt it is a big sink relative to organisms and other sinks, but I’ve never seen any useful data in that regard.

My ICP results keep showing the trace elements that go into chaeto grow, as missing.

So I thought to myself, I have a ton of rapidly growing chaeto in my sump that I harvest all the time, and I'm having to dose nitrate and phosphate. The initial logical conclusion was that the chaeto was stripping the elements listed on the bottle out of my water column and if I need to dose nutrients, then get rid of the chaeto. So I did. And I manually dosed the missing trace elements according to the bottles to bring them into the middle of the range.

2 weeks later, same elements are non detectable.

I'm working through what could be taking those elements up, and had hoped it was carbon as that is an easy fix. But that doesn't look promising.

I wouldn't even really care but it's a packed sps tank and I've lost some random healthy colonies recently. The icp operator thinks it's those deficient trace elements based on his testing. He evaluates what people write that is going on with their sample submission and I'm guessing anecdotally sees a pattern or connection to those elements not being present in enough quantities and connects them with the same complaints I have. Which are basically patchy lighter spots that start to develop on the underside of the corals and then slowly turn into stn. He seems to think the undersides of the colonies are more vulnerable to trace element deficiencies and that's where it starts to visibility show first.

Above my pay grade as the expression goes....

 

[Dan_P]

My macro algae grows very fast and it's quite obvious after it consumes all of the trace elements it needs to grow. This is when it starts to deteriorate. When I dose small amounts of ChaetoGro, it perks up the next day.

I want to start using activated carbon to remove odor and possibly toxins from corals. But will carbon media also soak up the trace elements from ChaetoGro? Will it also remove organics that the filter feeding hitchhiker and corals eat?

Chemical composition of ChaetoGro:

• potassium (1.3%)
• boron (0.009%)
• carbon (0.005%)
• calcium (0.14%)
• chlorine (0.39%)
• iron (0.32%)
• magnesium (0.4%)
• manganese (0.0475%)
• molybdenum (0.004%)
• cobalt (0.0004%)
• nickel (??)
• sulfur (0.16%)
• zinc (0.002%)

If what you say is true about the Cheato, use it as your “canary in the coal mine” for trace elements. Put in the GAC, and if the Cheato struggles, increase the dose of CheatoGro until it perks up. I would give it more than a day for the Cheato to respond to the dose increase. It is easy to add too much CheatoGro.

By the way, why does your aquarium stink?

 

[Randy Holmes-Farley Verified Community Expert]

My ICP results keep showing the trace elements that go into chaeto grow, as missing.

So I thought to myself, I have a ton of rapidly growing chaeto in my sump that I harvest all the time, and I'm having to dose nitrate and phosphate. The initial logical conclusion was that the chaeto was stripping the elements listed on the bottle out of my water column and if I need to dose nutrients, then get rid of the chaeto. So I did. And I manually dosed the missing trace elements according to the bottles to bring them into the middle of the range.

2 weeks later, same elements are non detectable.

I'm working through what could be taking those elements up, and had hoped it was carbon as that is an easy fix. But that doesn't look promising.

I wouldn't even really care but it's a packed sps tank and I've lost some random healthy colonies recently. The icp operator thinks it's those deficient trace elements based on his testing. He evaluates what people write that is going on with their sample submission and I'm guessing anecdotally sees a pattern or connection to those elements not being present in enough quantities and connects them with the same complaints I have. Which are basically patchy lighter spots that start to develop on the underside of the corals and then slowly turn into stn. He seems to think the undersides of the colonies are more vulnerable to trace element deficiencies and that's where it starts to visibility show first.

Above my pay grade as the expression goes....

All photosynthetic organisms use mostly the same basic set of trace elements.

 

[DeputyDog95]

All photosynthetic organisms use mostly the same basic set of trace elements.

Didn't know that. Assumed incorrectly, per usual... Not sure why my tank uses these in ratios atypical to what I would have thought were the averages.

 

[Randy Holmes-Farley Verified Community Expert]

Didn't know that. Assumed incorrectly, per usual... Not sure why my tank uses these in ratios atypical to what I would have thought were the averages.

Why do you think it’s atypical? It is very common to see zero on many needed trace elements by icp-OES, but that does not mean levels are too low.

 

[DeputyDog95]

Why do you think it’s atypical? It is very common to see zero on many needed trace elements by icp-OES, but that does not mean levels are too low.

Just assumed consumption would be linear. You have x number of corals consuming x amount of Ca and Alk, assumed incorrectly that the corals would consume x amount of trace elements.

I've since removed my refugium and the carbon to see what happens.