dissolved organics & nutrients, the same?

[fullmonti]

Are dissolved organics & nutrients (phosphate & nitrate etc) closely related, one in the same, or totally unrelated? I was wondering is it's possible to have high nutrient levels (phosphate & nitrate) & have low dissolved organics so a skimmer would have very little to skim?

Jim

 

[tmz]

They are different but they are all nutrients. Living thins need nitrogen, phosphorus and carbon to thrive. Many take much of their carbon from photosynthesis but still need some organic carbon.

An organic is a molecule that contains a hydrogen and a carbon atom. Many contain a vast array of other things including nitrogen , phosphorous and metals. Organics include theings like fats, ammino acids, proteins ,vitamins and toxins. They are generally hydrophobic( repelled by water) ; some are amphipathic ( drawn to water at one end and repelled at the other. The later are most susceptible to skimming as the molecule gets trapped in the air water interface and foamed out.

Inorganic phosphate( PO4 species) and inorganic nitrogen( ammonia, nitite, nitrate) bind stongly to the water and are not removable by a skimmer.

Many organics breakdown and release inorganic nitrogen and phosphate. Some organics are more refractory than others and resist breaking down. Exporting dissoved and particulate organics before they release inorganic nitrogen and phosphorous is why aquarists use skimming, granulated activated carbon and some resins to help nitrae and phospahte levels by getting at them before they are realeased by the organic molecules.

 

[fullmonti]

With my almost total lack of a scientific background, what I got out of that is they are kinda the same but different. Sorry.

If I may, let me tell you why I ask. I have a 7gal nano with a 5gal sump. It has three small fish & some large polyp nps corals I feed at night as well. I have a Tunze 9205 DOC skimmer in it, definitely over sized but i'm pretty heavily stocked & it would fit in limited overhead space. It doesn't skim much, so I held off on water changes a little to see if nutrients built up a little if it would skim more. It did not, but when I check nitrate & phosphate they were very high indeed. I wondered if a skimmer just couldn't get much out of a tank this size or if it was just not work properly.

I know this isn't just a water chemistry question, but I'm trying to figure out if this is all any skimmer could get out of a small system or if there is problem with the skimmer. This skimmer is a little odd in that the water coming in & going out come & go from the same place, kind of a recirculating skimmer. So if it's in to much flow it doesn't work properly. Tech at Tunze has been very helpful, just not sure if this is the way it should be.

Jim

 

[HighlandReefer]

You have basically two types (classifications) of stuff in your water:

1) Suspended Particles: which are larger than 0.25 microns in size. These include bacteria, algae, dinos and other micro-organisms. These include other particles larger than the 0.25 microns, for example calcium carbonate. Organic debris such as exrement and organism parts are included in this as well. The skimmer will remove these suspended particles.


2) Dissolved Chemicals: Which are smaller than 0.25 microns in size. These include the molecules which are very small in size. These include the inorganic molecules like nitrate & phosphate. They also include the organic molecules as Tom has described above. Skimmers will not remove the dissolved chemicals for the most part. To remove the dissolved organic molecules, you need to do water changes and run GAC. To remove nitrate & phosphate, usually you skim out bacteria that have incorporated them into their body structures.

 

[fullmonti]

OK thanks
That's about what I thought, but nice to know for sure.
It's a pretty new setup & I am running AC & a little GFO. Also just put a bag of bio media in. Guess I let it run awhile & see.
Jim