Flatlander uses an ATS. His setup can be found near the bottom of this
Thread. I have seen a monster ATS at Inland Aquatics. Here is an article where Morgan describes his
ATS system. More information on algae exportation can be found
Here.
Mikes post on the usefulness of algal filtration was extremely detailed but I would like to expand on it somewhat anyway.
Just like most methods of filtration, Algal Filtration comes with it's own set of issues and they should be discussed.
If you are using algae for filtration, it is important to run a quality carbon to remove the gelbstoff that the algae is putting into the water. There is a lot of info on carbon
here.
First lets point out the differences between an ATS and a regular macroalgae refugium. An ATS typically uses turf algaes as opposed to macroalgaes like caulerpa or Chaetomorpha. Turf algaes typically reproduce via fragmentation rather than sexually or budding or sporulation (although some algaes can reproduce both ways). Mechanical filtration would be highly recommended to prevent fragments from making it into the display tank to grow turf algae there. (This is why it's dangerous to manually rip hair algae while the rock is in the tank...you're just spreading fragments around. If possible, take the rock out and dunk it in waterchange water and do the ripping there and then rinse with fresh saltwater before putting it back into the tank. If this isn't possible, put in a filter sock or other mechanical filtration to catch the fragments).
The important thing to think about with algae is that it is sessile. It doesn't have the ability to run and hide when predators come around. As a result, they have come up with strategies to prevent predation. Most turf algaes just fragment to make sure that their offspring survive. However, most other macro's have another plan...
Activated Defense Systems.
Activated defenses against herbivores and predators are defenses whereby a precursor compound is stored in an inactive or mildly active form. Upon damage to the prey, the precursor is enzymatically converted to a more potent toxin or feeding deterrent.
This is the reason that most fish won't touch caulerpas, chaetos, halimedas, ulvas, etc. It's also the reason that it is very dangerous to move non-native macroalgaes like shown in the link Witfull posted. There is typically only a couple of predators that are immune to the toxins in an area. If the macroalgae gets transported to a different area where none of the herbivores have immunity, it overgrows everything.
In a reef tank, it's important to remember that the same porousness of the thallus that allows a macroalgae to absorb nasties also allows it to release tannins and toxins. A good percentage of the nasties that go into an algae, goes right back out. It's the equivalent of having what you say to your child go in one ear and out the other. This is one of the main reasons that if you are using algal filtration on a softy tank, I think you should use a fast growing species and export (properly) often. Why put up with the disadvantages of a macro but get very little exportation? JMO though.
reedman said:
Here's one to think about. What kind of tank does macro algae belong in? An SPS tank is about the worst conditions possible for macro, as we are trying to minimize nuutrients already with heavy skimming. For this type of tank I 100% agree with what Nikki says.
BINGO!!! Great point Reed. Putting macroalgae on a highly skimmed, nutrient poor system is a recipe for disaster. If they aren't getting enough nutrients, most macros will go "sexual" in the hope that their offspring will find enough nutrition to continue living. A number of macros are holocarpic and the whole organism becomes the reproductive structure. With holocarpic algaes, they aren't just releasing gametes. They are releasing the Nitrates, Phosphates, DOCs, and toxins as well as the entire cytoplasm and this puts a SEVERE strain on the dissolved Oxygen in the tank. Would you collect skimmate for a couple of weeks and then pour it all into your tank at once? That's basically what happens.
To add insult to injury, the "safe" precursor compound in caulerpa (caulerpenyne) is a toxin to SPS and it is constantly released as the algae respires. It doesn't even have to enzymatically turn into Oxytoxin (or be released sexually) to be dangerous to SPS. Halimedas are a pain....they don't go sexual as often as caulerpas but when they do, ALL of the algaes go sexual instead of just one plant. IMO, SPS tanks should not use algal filtration....only softy tanks. And even then it is necessary to prune properly. Now that you know about activated defense systems, what is the best way to prune and why?
