Allelopathy... scratching my head

Los

New member
This site is like family and I really appreciate so many people altruistically helping out folks like myself. If you can help me understand the following, I'd really appreciate your input.

I've had a periodic bout of slow tissue necrosis on some of my sps, going from the base up. The first time I had it, I tried everything and eventually concluded it might be phosphates. I rigged up a reactor with carbon and GFO and the problem was solved. A couple months later, after not having changed the GFO and carbon, I started experiencing the same thing along with some of my corals becoming quite faded. At this point, I still didn't have any fish in my main display (360 gallons, 600 total system) and was only adding a small amount of food for the corals and cleanup crew, but I figured since GFO had worked before, the problem was likely phosphates again. This time, though, I had a test kit and I had ZERO phosphates (Hanna - low range). I started thinking maybe the problem was too little phosphates, but since GFO had worked before, I replaced the media in my reactor and noticed an immediate improvement. The STN stopped and the colors once again started improving. I was left scratching my head at how such a low nutrient system could have a phosphate problem, which was unmeasurable by Hanna, but figured if it worked it worked. That was a couple of weeks ago.

Today I was reading about allelopathy. I checked my notes and the STN problem started around the time that I introduced some softies into my system and it wasn't lost on me that every time I "fixed" the problem with GFO, I was also replacing my carbon. Maybe the problem had nothing to do with phosphates and instead it was the carbon cleaning out some allelopathy chemicals. I had a large toadstool in my tank, a decent sized mat of green star polyps (GSP), and a large green kenya tree type coral. Before I get too many warnings on the speed at which GSP will spread, I should note that they are isolated on a rock which prevents them from spreading. Could it have been allelopathy all along?

What doesn't make sense to me, though, is how allelopathy could evolve in animals that are in the ocean. Most of these critters come from very large bodies of water (the ocean) with plenty of current (the ocean) where any energy spent on waging chemical warfare would be totally wasted. As soon as the animals release their chemicals, they would immediately be washed away and diluted to the point of being totally irrelevant. IF they were so incredibly toxic that they could work even diluted to the extent you'd expect in the ocean, you would think they would immediately fry anything in a closed system. It just doesn't make sense to me.

Can someone explain to me how allelopathy can be effective in the wild yet have such a relatively mild impact in a tank? I'm really scratching my head on this one. Also, what is the most likely offender? I got rid of the toadstool today and am wondering if the GSP need to go as well.
 
it's more of an immediate area effect that works in the ocean. It's not a system evolved to nuke everything in a ten foot area, just in the immediate area of new growth. It sounds like it's your problem, especially after you mentioning the leathers. IIRC, leathers, in the company of frogspawn, torch, etc. will release defensive chemicals in the water and this can cause tank-wide issues. I don't know if it's only in the presence of these corals that the leathers go to war. It may be triggered by any near by competitor. I'd be willing to bet that's your issue.
 
I'm just thinking with the bit of diving I have done that the concept of the scale is just not represented in aquariums. I have seen plating corals the size of Volkswagens and Acre sized patches of those garden eels. Elk-horn Coral that is more in line with the fence around a ball stadium than a specimen in a tank. Our tanks do not resemble the proper scale for things like this to function naturally.

I run into factual examples of terrestrial allelopathy every week in my line of work. All I can say is Nature is Chaos by its very nature.
 
And don't forget that perhaps not all of the compounds exuded by the aquarium inhabitants are MEANT to be allelopathic, just that they end up being that way in the confines of an aquarium.

Jay
 
How much allelopathic material get's taken out by gac, gfo ,puigen etc is unclear. Most of these organic chains are thought to be complex and might have less affinity for gac absorbtion than many think. I think though a leather close to sps is a bad bet overall. Been there where similar results.

BTW another culprit could be nitrate.
 
I appreciate everyone's input. Dose ozone help? I would think ozone could help break down those organic chains.
 
Don't use ozone yet( I have a generator and I am thinking about a a reactor design) but it should break down the carbon links in those chains.

Ozone may actually help gac (granulated activated carbon)perform more efficiently. Tests for total organic carbon(which would encompass allelopathic metabolites, I beleive) in a marine mamal pool, showed ozone removed 0%, that doesn't mean it didn't alter it, however. Granulated activated carbon without ozone removed about 32% of the organic carbon. Granulated activated carbon used with ozone removed over 70%. Presumably, the ozone altered the chains into forms with more affinity for gac absorbtion. I can't remember the link for the study but could find it if you need it.

BTW, I also think that purigen and gac work well together since each has affinities for different types of organics.
 
I have already separated my GFO and carbon so that a small maxi-jet 400 shoots the water first through a reactor with carbon and then a separate reactor with GFO. Would it make sense to first run the water through a reactor with ozone, then carbon, and then GFO? Or would it be better to run ozone in my skimmer (a BubbleKing 300 Internal). I realize this is a bit off topic, but if you happen to know...
 
From what I have been reading using the skimmer is a poor choice due to the degrading effects of ozone . Randy Holmes Farely wrote a nice set of articles on ozone including equipment and safety issues. They are in the set of articles listed nearthe top of the Reef Chemistry Forum. Ther ae also a couple of goos reads in the diy forum under ozone reactors.
 
If RHF has written about it, then that's where I'm going. Randy is awesome and one of the best contributors to this hobby. Thanks for the pointer, Tom.
 
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