What does Carbon Actually Remove From the Water?

[livinlifeinBKK]

So I love the water clarity carbon use provides but really don't want to strip the water of anything like vitamins, minerals, amino acids, etc. Just for a little additional clarity. From my understanding, it binds chemical contaminants like copper as well as some organics such as helping to control ammonia spikes. In regards to the starfish tank I just set up, I've been adding weekly doses of Brightwell's Vitamarin M since it's a brand new system and starfish can and do obtain some of their nutrition through dissolved organics in the water (like amino acids). If I added a bag of activated carbon would that strip many of the vitamins I just added? There aren't any fish in the system right now so I don't want the water completely devoid of vitamins and nutrients which is why I added the vitamin supplement, have been lightly ghost feeding, and add a little Phyto every night. The reason for the carbon would be due to the heater I had crack before adding anything to the system. I posted on here and mostly everyone concluded it should be fine but since stars are so sensitive I still worry a little...
So long story short will activated carbon strip the water of healthy vitamins and nitrates/phosphates (which are very low right now) as well as any copper which might not even be present?

 

[livinlifeinBKK]

@Randy Holmes-Farley I should've posted this in your section...I'm sure you know all about this

 

[Randy Holmes-Farley Verified Community Expert]

IMO, GAC binds a subset of the dissolved organic matter in a reef tank, and anything that is attached to those organics, such as trace metals.

I’m not convinced it binds metals directly in any important quantity, it won’t bind ammonia, nitrite, nitrate, or inorganic phosphate to any important degree.

I’ve not seen evidence that dissolved vitamins are desirable, but it would bind many if present. It would bind some, but not all amino acids.

 

[livinlifeinBKK]

IMO, GAC binds a subset of the dissolved organic matter in a reef tank, and anything that is attached to those organics, such as trace metals.

I’m not convinced it binds metals directly in any important quantity, it won’t bind ammonia, nitrite, nitrate, or inorganic phosphate to any important degree.

I’ve not seen evidence that dissolved vitamins are desirable, but it would bind many if present. It would bind some, but not all amino acids.

So why does it seem to help with water clarity so much? This is something I should already know but never completely thought it through tbh. With the vitamins, I'm not sure they'll help anything either but it seems having some nutrients/vitamins in the water may help with biofilm regrowth after the original biofilm has been eaten.

And where do amino acids naturally come from on a reef? They're actually pretty important for starfish nutrition from my research and they absorb them dissolved in the water...

 

[A Young Reefer]

Not to hijack this thread, but what are the negative effects of leaving carbon running for a long period time without replacing it? Will it start leaching those metals back into the water column?

 

[Herpdederp]

I was speaking to one of my LFS's owners and I was informed that activated carbon leaches trace elements as well as the main ones. I added a new bag two weeks ago, seems like my Mg levels are dropping a lot. But not sure if that's from corals or the carbon as I just balanced out the NO3 and PO4 chemistry a week prior to adding the carbon. Not sure how much of the carbon leech is true. I haven't been able to find any good articles on this topic.

 

[Randy Holmes-Farley Verified Community Expert]

I was speaking to one of my LFS's owners and I was informed that activated carbon leaches trace elements as well as the main ones. I added a new bag two weeks ago, seems like my Mg levels are dropping a lot. But not sure if that's from corals or the carbon as I just balanced out the NO3 and PO4 chemistry a week prior to adding the carbon. Not sure how much of the carbon leech is true. I haven't been able to find any good articles on this topic.

Do you mean leach (which means release), or bind?

GAC has no detectable impact on magnesium (not a trace element) in any reef aquarium.

Magnesium also never really drops more than 1-2 ppm per day. Anything more than that is test error or a salinity drop.

 

[Herpdederp]

Do you mean leach (which means release), or bind?

GAC has no detectable impact on magnesium (not a trace element) in any reef aquarium.

Magnesium also never really drops more than 1-2 ppm per day. Anything more than that is test error or a salinity drop.

I mean bind, hmmm wonder what is lowing Mg so rapidly. The only thing I added recently is the chemi-pure blue carbon. Actually come to think of it I lowered the SG from 1.025 to 1.024, could explain the drop.

 

[Randy Holmes-Farley Verified Community Expert]

A lowering of sg from 1.025 to 1.024 will lower magnesium from 1300 ppm to 1248 ppm.