filtration???

[aqua_chem]

I don't know much about corals or their needs, so I won't comment on that. The reason that I lumped HITH and HLLE is because carbon has been claimed to be a cause in both. I don't really deal with larger cichlids, so I don't have a great deal of knowledge on their diseases. The idea that something missing from the water causes an external pathology is pretty odd from my understanding of fish anatomy. My understanding is that they rely very little on absorption from their surroundings for key nutritional or demands. "Carbon Dust" just makes more sense to me, as very small particulates could be an irritant to the sensitive lateral line organ. While "carbon dust" has not been proved, to my knowledge a mechanism for HLLE has not been suggested. If you have read something, I would like to hear it. That's not intended to be snarky; it would actually be very interesting.

As far as corals, I will fully admit that I know absolutely squat about their biology, dietary needs, etc. Do they make their own vitamins? Do they use dissolved organics? Heck if I know. I will, however, point out that they are a different classification of life altogether from plants, so they would conceivably be different.

As far as the salts matter goes, I stand by the statement that most of what we dose is a salt. The one fertilizer company that railed against it included vitamins and auxins in their product, which is odd considering that an autotrophic organism like a plant makes its own vitamins... and no other fertilizer contains it.


I will, however, say that since we've been having this discussion, I've been looking through some journals about activated carbon and EDTA complexed metals. Some of them implicated that the chelated metals are indeed slowly adsorb onto activated carbon. So there's that. Interesting. However, some of them say that the complex slowly breaks apart over 12-48 hours regardless of if it is adsorbed or not, releasing the metal for use by plants. So while it complexing agents might end up on the carbon, the metal is still going to be released for your plants. I used carbon for a long time in aquaclear filters and never saw deficiencies, which would make sense if they are available to plants even after adsorption. DTPA probably won't have this issue at all though, nor will the normal metals salts, like the Iron Sulfate in flourish.

As an aside, I do appreciate the discussion.

 

[Fishguy2727]

Exactly, most, not all of what we add (assuming that is all plants need) is salts, not all of it. So there are things they need that are not salts, my point exactly.

Carbon is claimed as a cause for HITH and HLLE because they are always lumped together because the symptoms are so similar, basically 'holes in the head' and 'holes in the head and along the lateral line'. They are not the same and when people start to realize this the discussions about them will be more productve since you won't have discus people AND oscar people thinking they are talking about the same thing when they really aren't. I don't think irritating the lateral line would be enough, something more drastic has to happen, I don't buy the carbon idea.

External symptoms doesn't mean external pathology. One of the ideas with the parasites is that it is a whole body infection but the only thing we can see are the holes on the outside. The lateral line system is highly vascularized so there are a lot of small blood vessels where the parasites can physically block blood flow, causing those areas to necrose. We can only see it if it happens externally, but it may be happening internally as well (which would explain why it actually kills the fish). Since the parasites specified previously have been shown to infect many difference organs and body systems, this idea seems well founded. It is as if we went to the doctor and he said 'well, there are no big holes in you, no white fuzz growing on your fingers, no big red streaks from massive bacterial infections, you must be fine'. Our understanding of fish disease and pathology is so bad that they have to have such a massive problem it becomes externally visible. This is why so many times fish die well before their years with no apparent symptoms, then we call it 'old age' and think we did a good job.

Corals do get a lot from the water column, some needing nothing more than what is dissolved in the water and what is produced by photsynthesis by their endosymbiont algae partners. So it is like an exaggerated version of a plant, in a way. Plants carry out photosynthesis but still need a lot from the water.

The idea that carbon could cause HLLE in cichlids is a bit trickier and the reasoning or method is not as well understood. One idea is that they do need at least some things from the water, if carbon removes them they may not be able to get them nutritionally. The lack of a certain vitamin or mineral could cause enough of a problem so that certain proteins, enzymes, or something doesn't work properly in the body, which could cause HLLE.

The good/bad part is that carbon use in reefs and planted tanks is only problematic if everything else is so well balanced that the micronutrients and/or vital trace elements that it removes have to be the limiting factor. In most tanks there are much larger issues that are the limiting factor (like light, carbon diozide, ferts/nutrients, etc.). Few tanks are so 'perfect' that what carbon removes actually has effects.